Tiletamine Zolazepam Research Articles

Evaluation of Dexmedetomidine with Tiletamine-Zolazepam for Snow Leopard (Panthera uncia) Immobilization.

This study describes two different doses of dexmedetomidine combined with tiletamine-zolazepam (TZ) for anesthesia in snow leopards (Panthera uncia). A total of 11 adult snow leopards were anesthetized in Xining City, Qinghai Province, China from November 2019 to June 2023. We recorded the onset time, anesthesia duration, head-up time, and walking time. Vital signs were recorded every 5 min during anesthesia. Arterial blood gas analysis was performed approximately 20 min after the onset of anesthesia by collecting blood from the femoral artery. All results were presented as mean±SD. There were no significant differences in onset time, anesthesia duration, head-up time, and walking time between the two anesthesia protocols. Heart rate, respiratory rate, body temperature, and blood pressure had a gradual decreasing trend, and blood oxygen saturation gradually increased. Our results suggest that using dexmedetomidine at doses of 21.25±1.38 μg/kg to 30.95±1.13 μg/kg combined with TZ at 2.07±0.08 mg/kg to 2.13±0.15 mg/kg can provide safe and effective anesthesia for snow leopards.

A Retrospective Comparison of Electrocardiographic Parameters in Ketamine and Tiletamine-Zolazepam Anesthetized Indian Rhesus Monkeys (Macaca mulatta).

Electrocardiographic evaluation is performed in rhesus monkeys to establish the cardiovascular safety of candidate molecules before progressing to clinical trials. These animals are usually immobilized chemically by ketamine (KTM) and tiletamine-zolazepam (TZ) to obtain a steady-state heart rate and to ensure adequate human safety. The present study aimed to evaluate the effect of these anesthetic regimens on different electrocardiographic parameters. Statistically significant lower HR and higher P-wave duration, RR, QRS, and QT intervals were observed in the KTM-anesthetized group in comparison to TZ-anesthetized animals. No significant changes were noticed in the PR interval and p-wave amplitude. Sex-based significance amongst these parameters was observed in male and female animals of TZ- and KTM-anesthetized groups. Regression analysis of four QTc formulas in TZ-anesthetized rhesus monkeys revealed that QTcNAK (Nakayama) better corrected the QT interval than QTcHAS (Hassimoto), QTcBZT (Bazett), and QTcFRD (Fridericia) formulas. QTcNAK exhibited the least correlation with the RR interval (slope closest to zero and r = .01) and displayed no statistical significance between male and female animals. These data will prove useful in the selection of anesthetic regimens for chemical restraint of rhesus monkeys in nonclinical safety evaluation studies.

Effects of tiletamine-zolazepam vs. propofol on peri-induction intraocular pressure in dogs: A randomized, masked crossover study.

Anesthesia induction agents have the potential to cause severe ocular side effects, resulting in lasting damage to the eye. The purpose of this study is to determine the effects of tiletamine-zolazepam on IOP compared to propofol when they are used as an induction agent in normal healthy dogs. Twenty healthy adult client owned dogs weighing 22.2 ± 7.6 kg were selected for the study. In a randomized order, all dogs received tiletamine-zolazepam 5 mg/kg IV or propofol 8 mg/kg IV titrated to effect without premedication. Washout between each treatment was at least seven days. IOP measurements were obtained at four time points: baseline, post-induction, post-intubation, and after recovery using applanation tonometry. No additional procedures were performed. After normality of the data was determined, a linear mixed model was built with time, eye, treatment and all interactions of those variables as fixed effects and subject as a random effect. There was no significant difference for age, body weight, drug dose, baseline IOP, and recovery IOP between treatments. Average IOP measurements remained within the normal range of 15-25 mmHg at these time points. However, IOP was significantly less elevated by the tiletamine-zolazepam treatment vs. propofol at the post-induction (mean difference: -4.7 ± 4.6 [95%CI -6.8 to -2.5]) and the post-intubation (mean difference: -4.4 ± 4.6 [95%CI -6.5 to -2.2]) time points. Dogs receiving tiletamine-zolazepam for anesthetic induction had a significantly less elevated IOP at induction and intubation compared to dogs receiving propofol.

Comparison of the cardiovascular effects of immobilization with three different drug combinations in free-ranging African lions.

Thirty-six free-ranging lions (12 per group) were immobilized with tiletamine-zolazepam (Zoletil 0.6mg/kg i.m.) plus medetomidine (0.036mg/kg i.m.) (TZM), ketamine (3.0mg/kg i.m.) plus medetomidine (0.036mg/kg i.m.) (KM) or ketamine (1.2mg/kg i.m.) plus butorphanol (0.24mg/kg i.m.) plus medetomidine (0.036mg/kg i.m.) (KBM). During immobilization cardiovascular variables were monitored at 5-minute intervals for a period of 30minutes. Lions immobilized with all three drug combinations were severely hypertensive. Systolic arterial pressure was higher at initial sampling in lions immobilized with KM (237.3 ± 24.8mmHg) than in those immobilized with TZM (221.0 ± 18.1mmHg) or KBM (226.0 ± 20.6mmHg) and decreased to 205.8 ± 19.4, 197.7 ± 23.7 and 196.3 ± 17.7mmHg, respectively. Heart rates were within normal ranges for healthy, awake lions and decreased throughout the immobilization regardless of drug combination used. Lions immobilized with TZM had a higher occurrence (66%) of skipped heart beats than those immobilized with KBM (25%). The three drug combinations all caused negative cardiovascular effects, which were less when KBM was used, but adverse enough to warrant further investigations to determine if these effects can be reversed or prevented when these three combinations are used to immobilize free-living lions.

Immobilization of Captive Kulans (Equus hemionus kulan) Without Using Ultrapotent Opioids.

Etorphine is widely used in zoological medicine for the immobilization of large herbivores. All reported immobilization protocols for kulans use etorphine as the primary immobilizing agent. However, etorphine can trigger severe side effects and is highly toxic for humans, its availability is occasionally limited for use in wildlife medicine. Therefore, two different alpha-2 agonist-based protocols for the general anesthesia of kulans were investigated and compared with the standard etorphine immobilization. In total, 21 immobilizations were performed within the scope of routine husbandry management at the Serengeti-Park Hodenhagen. Kulans were darted using a ketamine–medetomidine–midazolam–butorphanol (KMMB) protocol (n = 8, treatment group (TG) 1), a tiletamine–zolazepam–medetomidine–butorphanol (TZMB) protocol (n = 7, treatment group (TG) 2), or an etorphine–acepromazine–detomidine–butorphanol (EADB) protocol (n = 6, control group). Vital parameters included heart rate, respiratory rate, arterial blood pressure (invasive), end tidal CO2 (etCO2), electromyography and core body temperature, which were all assessed every 10 min. For blood gas analysis, arterial samples were collected 15, 30, 45 and 60 min after induction. Subjective measures of quality and efficacy included quality of induction, immobilization, and recovery. Time to recumbency was longer for TG 1 (9.00 ± 1.67 min) and TG 2 (10.43 ± 1.79 min) compared to the induction times in the control group (5.33 ± 1.93 min). Treatment group protocols resulted in excellent muscle relaxation, normoxemia and normocapnia. Lower pulse rates combined with systolic arterial hypertension were detected in the alpha-2 agonist-based protocols. However, only in TZMB-immobilized kulans, sustained severe systolic arterial hypertension was observed, with significantly higher values than in the TG 1 and the normotensive control group. At 60 min following induction, medetomidine and detomidine were antagonized with atipamezole IM (5 mg/mg medetomidine or 2 mg/mg detomidine), etorphine and butorphanol with naltrexone IV (2 mg/mg butorphanol or 50 mg/mg etorphine), and midazolam and zolazepam with flumazenil IV (0.3 mg per animal). All three combinations provided smooth and rapid recoveries. To conclude, the investigated treatment protocols (KMMB and TZMB) provided a safe and efficient general anesthesia in kulans with significantly better muscle relaxation, higher respiration rates and improved arterial oxygenation compared with the immobilizations of the control group. However, the control group (EADB) showed faster recoveries. Therefore, EADB is recommended for ultra-short immobilizations (e.g., microchipping and collaring), especially with free-ranging kulans where individual recovery is uncertain, whereas the investigated treatment protocols are recommended for prolonged medical procedures on captive kulans.

Comparison of Alfaxalone-Midazolam, Tiletamine-Zolazepam, and KetamineAcepromazine Anesthesia during Plethysmography in Cynomolgus Macaques (Macaca fascicularis) and Rhesus Macaques (Macaca mulatta).

Plethysmography is used in nonhuman primates (NHPs) to measure minute volume before aerosol exposure to an agent to calculate total time necessary in the exposure chamber. The consistency of respiratory parameters during the entire exposure time is paramount to ensuring dosing accuracy. Our study sought to validate an alfaxalone-midazolam (AM) anesthetic combination for use in aerosol studies. We hypothesized that AM would provide an adequate duration of anesthesia, achieve and maintain steady state minute volume (SSMV) for 20 min, and have anesthetic quality and side effects comparable to or better than either tiletamine-zolazepam (TZ) and ketamine-acepromazine (KA), the most common anesthetics used for this purpose currently. Two groups of NHPs, one consisting of 15 cynomolgus macaques and one of 15 rhesus macaques, received 3 intramuscular anesthetic combinations (AM, TZ, and KA), no less than one week apart. Anesthetized NHPs were placed in a plethysmograph chamber and their minute volumes were measured every 10 s to determine whether they had achieved SSMV and maintained it for at least 20 consecutive min. Achieving and reliably maintaining an SSMV for at least 20 min facilitates precise aerosol dosing of a challenge agent. Quality of anesthesia, based on the NHP's ability to achieve and maintain SSMV, was higher with AM compared with TZ and KA in both species, and AM had a longer duration of SSMV as compared with TZ and KA in cynomolgus macaques. Average SSMV was larger with AM compared with TZ in cynomolgus macaques, but larger with KA compared with AM in rhesus macaques. Duration of anesthesia was sufficient with all combinations but was longer for TZ than both AM and KA in both species. These results suggest that the AM anesthetic combination would produce the most accurate dosing for an aerosol challenge.

Determination of the effective dosage of tiletamine–zolazepam–ketamine–xylazine, with or without methadone, in dogs

ObjectiveTo determine the effective dosage of the combination tiletamine–zolazepam–ketamine–xylazine (TKX), with or without methadone, in dogs. Study designProspective, randomized, experimental study. AnimalsA total of 29 dogs. MethodsDogs were randomly administered TKX (group TKX, n = 13) or combined with 0.3 mg kg–1 of methadone (group TKXM, n = 16) intramuscularly. The TKX solution contained tiletamine (50 mg mL–1), zolazepam (50 mg mL–1), ketamine (80 mg mL–1) and xylazine (20 mg mL–1). The effective dosages for immobility in 50% and 95% of the population (ED50 and ED95) were estimated using the up-and-down method. Approximately 20 minutes after drug administration, a skin incision was performed and the response was judged as positive or negative if the dogs moved or did not move, respectively. The TKX volume for the subsequent dog in the same group was increased or decreased by 0.005 mL kg–1 if the response of the previous dog was positive or negative, respectively. Heart and respiratory rates, and sedation/anesthesia scores (range 0–21) were recorded before and 15 minutes after drug administration. ResultsEstimated ED50 and ED95 (95% confidence intervals) were: TKX, 0.025 (0.020–0.029) and 0.026 (0.010–0.042) mL kg–1; TKXM, 0.022 (0.018–0.025) and 0.033 (0.017–0.049) mL kg–1. Median (interquartile range) scores for sedation/anesthesia were 17 (16–18) and 17 (15–20), and times until lateral recumbency were 5 (4–6) and 6 (4–10) minutes in TKX and TKXM, respectively (p > 0.05). In both groups heart and respiratory rates decreased, but values remained acceptable for anesthetized dogs. Conclusions and clinical relevanceThe results provide a guide for volumes of TKX and TKXM in dogs requiring restraint for minimally invasive procedures. Inclusion of methadone in the TKX combination did not influence ED50.

Comparative Study of the Aftereffect of CO2 Inhalation or Tiletamine-Zolazepam-Xylazine Anesthesia on Laboratory Outbred Rats and Mice.

CO2 inhalation is currently the most common method of euthanasia for laboratory rats and mice, and it is often used for further terminal blood sampling for clinical biochemical assays. Lately, this method has been criticized due to animal welfare issues associated with some processes that develop after CO2 inhalation. The stress reaction and the value of the clinical laboratory parameters significantly depend on the used anesthetics, method, and the site of blood sampling. Especially in small rodents, an acute terminal state followed by a cascade of metabolic reactions that can affect the studied biochemical profile may develop and cause unnecessary suffering of animals. The aim of this study was to compare the stability of biochemical parameters of outbred Sprague Dawley rats and CD-1 mice serum collected after CO2 inhalation or the intramuscular injection of tiletamine–zolazepam–xylazine (TZX). The serum content of total protein and albumin, cholesterol, triglycerides, aspartate aminotransferase (AST), alanine aminotr ansferase (ALT), alkaline phosphatase (ALP), total bilirubin, and creatinine was decreased by the injection of TZX in comparison with CO2 inhalation. In addition, the levels of calcium, phosphates, chlorides and potassium were lowered by TZX vs. CO2 administration, while the level of sodium increased. Finally, the level of the majority of serum clinical biochemical parameters in rats and mice tend to be overestimated after CO2 inhalation, which may lead to masking the possible effect of anti-inflammatory drugs in animal tests. Injection anesthesia for small rodents with TZX is a more feasible method for terminal blood sampling, which also reduces the suffering of animals.

Evaluation of Tiletamine–Zolazepam Sedation in Central Bearded Dragons (Pogona vitticeps) Following Intramuscular and Subcutaneous Administration

The objective of this study was to evaluate the effects of tiletamine–zolazepam as a sedative drug in central bearded dragons (Pogona vitticeps) and determine if efficacy differed based on administration route. Ten healthy, adult central bearded dragons received tiletamine–zolazepam (20 mg/kg) either intramuscularly (IM) or subcutaneously (SC) in the cranial body in a randomized, blinded, complete crossover study with a minimum washout period of 2 wk between treatments. Respiratory rate, heart rate, body position, response to restraint, spontaneous movement, righting reflex, and jaw tone were evaluated. All bearded dragons received flumazenil (0.05 mg/kg, SC) in the cranial body 45 min after the initial tiletamine–zolazepam injection. Righting reflex was lost in all bearded dragons receiving tiletamine–zolazepam IM, but only half of the animals lost righting reflex after SC injection. Jaw tone was lost in 90% (9/10) of animals receiving IM injections compared to 40% (4/10) following SC injections. Recovery from sedation was similar between route of administration (IM: 69 ± 39 min, SC: 57 ± 33 min, P= 0.43). Postsedation food intake was suppressed 2 h after return of righting reflex. Based on the findings of this study, IM administration of tiletamine–zolazepam results in a deeper and more consistent plane of sedation in bearded dragons when compared to the SC route. Prolonged recoveries were noted with both routes of administration.

THE INFLUENCE OF ANESTHESIA WITH AND WITHOUT MEDETOMIDINE ON CARDIAC STRUCTURE AND FUNCTION IN SANCTUARY CAPTIVE CHIMPANZEES (PAN TROGLODYTES).

Dependent on timing of assessment, anesthetic agents and specifically medetomidine negatively affect cardiac function in great apes. The aim of this study was to determine the influence of tiletamine-zolazepam (TZ) with and without medetomidine on cardiac structure and function in healthy chimpanzees (Pan troglodytes) during a period of relative blood pressure stability. Twenty-four chimpanzees living in an African wildlife sanctuary undergoing routine health assessments were stratified by age, sex, and body mass and randomized to be anesthetized using either TZ (6 mg/kg; n = 13; seven males and six females) or a combination of TZ (2 mg/kg) and medetomidine (TZM; 0.02 mg/kg; n = 11; five males and six females). During health checks, regular heart rate and blood pressure readings were taken and a standardized echocardiogram was performed 20-30 min after induction. Data were compared between the two anesthetic groups using independent-samples t or Mann-Whitney U tests. Although heart rate (mean ± SD; TZ: 76 ± 10 bpm; TZM: 65 ± 14 bpm, P = 0.027), cardiac output (TZ: 3.0 ± 0.7 L/min; TZM: 2.4 ± 0.7 L/min, P = 0.032), and mitral A-wave velocities (TZ: 0.51 ± 0.16 cm/s; TZM: 0.36 ± 0.10 cm/s, P = 0.013) were lower in the TZM group, there were no statistically significant differences in cardiac structure or the remaining functional variables between groups. Furthermore, there were no statistical differences in systolic (TZ 114.6 ± 14.9 mmHg; TZM: 123.0 ± 28.1 mmHg; P = 0.289) or diastolic blood pressure (TZ: 81.8 ± 22.3 mmHg, TZM: 83.8 ± 20.1 mmHg; P = 0.827) between the groups during the echocardiogram. This study has shown that during a period of relative blood pressure stability, during the first 20-30 min after induction there are few differences in measures of cardiac structure and function between protocols using TZ with or without medetomidine in healthy chimpanzees.

Evaluation of intramuscular anesthetic protocols in healthy domestic horses

ObjectiveTo assess anesthetic induction, recovery quality and cardiopulmonary variables after intramuscular (IM) injection of three drug combinations for immobilization of horses. Study designRandomized, blinded, three-way crossover prospective design. AnimalsA total of eight healthy adult horses weighing 470–575 kg. MethodsHorses were administered three treatments IM separated by ≥1 week. Combinations were tiletamine–zolazepam (1.2 mg kg−1), ketamine (1 mg kg−1) and detomidine (0.04 mg kg−1) (treatment TKD); ketamine (3 mg kg−1) and detomidine (0.04 mg kg−1) (treatment KD); and tiletamine–zolazepam (2.4 mg kg−1) and detomidine (0.04 mg kg−1) (treatment TD). Parametric data were analyzed using mixed model linear regression. Nonparametric data were compared using Skillings–Mack test. A p value <0.05 was considered statistically significant. ResultsAll horses in treatment TD became recumbent. In treatments KD and TKD, one horse remained standing. PaO2 15 minutes after recumbency was significantly lower in treatments TD (p < 0.0005) and TKD (p = 0.001) than in treatment KD. Times to first movement (25 ± 15 minutes) and sternal recumbency (55 ± 11 minutes) in treatment KD were faster than in treatments TD (57 ± 17 and 76 ± 19 minutes; p < 0.0005, p = 0.001) and TKD (45 ± 18 and 73 ± 31 minutes; p = 0.005, p = 0.021). There were no differences in induction quality, muscle relaxation score, number of attempts to stand or recovery quality. Conclusions and clinical relevanceIn domestic horses, IM injections of tiletamine–zolazepam–detomidine resulted in more reliable recumbency with a longer duration when compared with ketamine–detomidine and tiletamine–zolazepam–ketamine–detomidine. Recoveries were comparable among protocols.

Field Anesthesia of the Maned Wolf (Chrysocyon brachyurus) in Bolivia.

Fifteen maned wolves (Chrysocyon brachyurus) were anesthetized a total of 43 times as part of a long-term ecology and health study in a remote region of northeastern Bolivia. We administered tiletamine-zolazepam (TZ) to wolves in box traps or free-ranging, from blinds or on foot, at a mean dosage of 4.6 mg/kg intramuscularly. Detailed anesthetic information was recorded in 24 of these events in 11 wolves (six males, five females), and wolves were monitored closely post procedure with very high frequency or global positioning system telemetry collars. Anesthetic induction was smooth and rapid in all cases, with a mean 6.4 min from injection to recumbency. Vital parameters were stable during the majority of procedures. As expected with this drug combination, recovery was long (mean time to standing 163 min [range: 80-235 min]) but smooth, and animals were monitored in most cases in box traps until stable for release. One case of apnea and prolonged recovery is reported. In two cases, wolves recovered normally but were found to move minimally in the 2.5-4 d postprocedure before resuming normal movements. Overall, TZ provided safe, stable immobilization of free-ranging maned wolves in remote and extreme field conditions, although postanesthesia monitoring via telemetry is recommended.

Physiologic and blood gas effects of xylazine–ketamine versus xylazine–tiletamine–zolazepam immobilization of white-tailed deer before and after oxygen supplementation: a preliminary study

ObjectiveTo compare oxygenation and ventilation in white-tailed deer (Odocoileus virginianus) anesthetized with two treatments with and without oxygen supplementation. Study designRandomized, blinded, crossover study. AnimalsA total of eight healthy adult white-tailed deer weighing 49–62 kg. MethodsEach deer was anesthetized twice intramuscularly: 1) treatment XK, xylazine (2 mg kg–1) and ketamine (6 mg kg–1) and 2) treatment XTZ, xylazine (2 mg kg–1) and tiletamine–zolazepam (4 mg kg–1). With the deer in sternal position, arterial and venous blood was collected before and at 30 minutes during administration of oxygen at 1 L minute–1 through a face mask. PaO2 and heart rate (HR) were compared using two-way repeated measures anova. pH, PaCO2 and lactate concentration were analyzed using mixed-effects linear models, p < 0.05. ResultsWhen breathing air, PaO2 was < 80 mmHg (10.7 kPa) in six and seven deer with XK and XTZ, respectively, and of these, PaO2 was < 60 mmHg (8.0 kPa) in three and five deer, respectively. With oxygen supplementation, PaO2 increased to 128 ± 4 and 140 ± 5 mmHg (17.1 ± 0.5 and 18.7 ± 0.7 kPa), mean ± standard error, with XK and XTZ, respectively (p < 0.001). PaO2 was not significantly different between treatments at either time point. HR decreased during oxygen supplementation in both treatments (p < 0.001). Lactate was significantly lower (p = 0.047) with XTZ than with XK (2.2 ± 0.6 versus 3.5 ± 0.6 mmol L–1) and decreased (p < 0.001) with oxygen supplementation (4.1 ± 0.6 versus 1.6 ± 0.6 mmol L–1). PaCO2 increased in XTZ during oxygen breathing. Conclusions and clinical relevanceTreatments XK and XTZ resulted in hypoxemia, which responded to oxygen supplementation. Both treatments are suitable for immobilization of white-tailed deer under the study circumstances.

Comparison of anesthetic effects of tiletamine–zolazepam–medetomidine or ketamine–medetomidine in captive Amur leopard cats (Prionailurus bengalensis euptailurus)

ObjectiveTo evaluate the effects and utility of tiletamine–zolazepam–medetomidine (TZM) and ketamine–medetomidine (KM) for anesthesia of Amur leopard cats (Prionailurus bengalensis euptailurus). Study designProspective, randomized experimental trial. AnimalsA total of six female (3.70 ± 0.49 kg) and six male (5.03 ± 0.44 kg; mean ± standard deviation) Amur leopard cats aged 2–6 years. MethodsEach animal was administered four protocols separated by ≥3 weeks. Each protocol included medetomidine (0.05 mg kg–1) combined with tiletamine–zolazepam (1 mg kg–1; protocol MTZLO); tiletamine–zolazepam (2 mg kg–1; protocol MTZHI); ketamine (2 mg kg–1; protocol MKLO); or ketamine (4 mg kg–1; MKHI) administered intramuscularly. At time 0 (onset of lateral recumbency) and 30 minutes, heart rate (HR), respiratory rate (fR), rectal temperature, noninvasive mean arterial pressure (MAP) and hemoglobin oxygen saturation (SpO2) were recorded. Times to onset of lateral recumbency, duration of anesthesia and time to standing were recorded. ResultsOverall, animals were anesthetized with all protocols within 10 minutes, anesthesia was maintained ≥57 minutes, and recovery (time from the first head lift to standing) was completed within 5 minutes. During anesthesia with all protocols, HR, fR, rectal temperature, SpO2 and MAP were 99–125 beats minute–1, 33–44 breaths minute–1, 37.6–39.4 °C, 90–95% and 152–177 mmHg, respectively. No adverse event was observed. Conclusions and clinical relevanceTZM and KM at various dosages resulted in rapid onset of anesthesia, duration of >57 minutes and rapid recovery without administration of an antagonist. Accordingly, all these combinations are useful for anesthetizing Amur leopard cats and for performing simple procedures. However, the low doses of the anesthetic agents are recommended because there was no difference in duration of anesthesia between the dose rates studied.

Effect of Xylazine–Tiletamine–Zolazepam on the Local Field Potential of the Rat Olfactory Bulb

Neural oscillations of the mammalian olfactory system have been studied for decades. This research suggests they are linked to various processes involved in odor information analysis, depending on the vigilance state and presentation of stimuli. In addition, the effects of various anesthetics, including commonly used ones like chloral hydrate, pentobarbital, ketamine, and urethane, on the local field potential (LFP) in the olfactory bulb (OB) have been studied. In particular, the combination of xylazine and tiletamine-zolazepam has been shown to produce steady anesthesia for an extended period and relatively few adverse effects; however, their effects on the LFP in the OB remain unknown. To study those effects, we recorded the LFP in the OB of rats under xylazine-tiletamine-zolazepam anesthesia. During the period of anesthesia, the spectral powers of the 1-4, 9-16, 31-64, 65-90 frequency bands increased significantly, and that of 91-170 Hz frequency band decreased significantly, whereas no significant changes were observed in the 5-8 and 17-30 Hz ranges. These results reveal dynamic changes in the time and frequency characteristics of the LFP in the OB of rats under xylazine-tiletamine- zolazepam anesthesia and suggest that this combination of anesthetics could be used for studying oscillatory processes in the OB of rats.

Investigação parasitológica e molecular de Toxoplasma gondii em urina e saliva de felinos (Felis catus) infectados experimentalmente

O objetivo do estudo foi investigar a presença de Toxoplasma gondii em amostras de urina e saliva colhidas de felinos experimentalmente infectados, fato inédito na literatura consultada. Seis felinos machos, sorologicamente negativos (IgG) para T. gondii, foram distribuídos em dois grupos, sendo quatro inoculados com 2x 105 taquizoítos (Cepa RH) via subcutânea (GI), e dois mantidos como controle (GII). Anteriormente à inoculação (dias -7 e 0) e no 7º, 14º, 21º, 28º, 42º, 56º e 70º dia pós-inoculação (DPI), os felinos foram anestesiados com tiletamina + zolazepam (na dose de 15 mg/kg,via intramuscular), sendo colhidas amostras de urina, saliva e sangue. Nas amostras sanguíneas obtidas após a inoculação, pesquisou-se a presença de anticorpos anti-T. gondii (IgG) pela reação de imunofluorêscencia indireta (RIFI). A parasitemia pelo T. gondii foi avaliada por meio de inoculações intraperitoneais em camundongos albinos (bioensaio). A pesquisa do T. gondii nas amostras de urina e saliva foram realizadas pelas técnicas de nested PCR e bioensaio em camundongos. Todos os felinos inoculados com T. gondii (GI) soroconverteram à infecção toxoplásmica, diferentemente dos felinos do não inoculados (GII), que permaneceram negativos durante todo estudo. Diagnosticou-se parasitemia pelo T. gondii em todos felinos do grupo I, totalizando cinco eventos entre o 7° e 42º DPI. Em nenhuma amostra de urina e saliva dos felinos GI e GII, diagnosticou-se a presença de T. gondii. Observou-se que felinos infectados experimentalmente com taquizoítos da cepa RH (isolado I) de T. gondii, podem não eliminar formas infectantes do parasito pela urina e saliva.

Cardiovascular effects of intravenous vatinoxan (MK-467) in medetomidine–tiletamine–zolazepam anaesthetised red deer (Cervus elaphus)

ObjectiveTo determine the effect of intravenous vatinoxan administration on bradycardia, hypertension and level of anaesthesia induced by medetomidine–tiletamine–zolazepam in red deer (Cervus elaphus). Study design and animalsA total of 10 healthy red deer were included in a randomised, controlled, experimental, crossover study. MethodsDeer were administered a combination of 0.1 mg kg–1 medetomidine hydrochloride and 2.5 mg kg–1 tiletamine–zolazepam intramuscularly, followed by 0.1 mg kg–1 vatinoxan hydrochloride or equivalent volume of saline intravenously (IV) 35 minutes after anaesthetic induction. Heart rate (HR), mean arterial blood pressure (MAP), respiration rate (fR), end-tidal CO2 (Pe′CO2), arterial oxygen saturation (SpO2), rectal temperature (RT) and level of anaesthesia were assessed before saline/vatinoxan administration (baseline) and at intervals for 25 minutes thereafter. Differences within treatments (change from baseline) and between treatments were analysed with linear mixed effect models (p < 0.05). ResultsMaximal (81 ± 10 beats minute–1) HR occurred 90 seconds after vatinoxan injection and remained significantly above baseline (42 ± 4 beats minute–1) for 15 minutes. MAP significantly decreased from baseline (122 ± 10 mmHg) to a minimum MAP of 83 ± 6 mmHg 60 seconds after vatinoxan and remained below baseline until end of anaesthesia. HR remained unchanged from baseline (43 ± 5 beats minute–1) with the saline treatment, whereas MAP decreased significantly (112 ± 16 mmHg) from baseline after 20 minutes. Pe′CO2, fR and SpO2 showed no significant differences between treatments, whereas RT decreased significantly 25 minutes after vatinoxan. Level of anaesthesia was not significantly influenced by vatinoxan. Conclusions and clinical relevanceVatinoxan reversed hypertension and bradycardia induced by medetomidine without causing hypotension or affecting the level of anaesthesia in red deer. However, the effect on HR subsided 15 minutes after vatinoxan IV administration. Vatinoxan has the potential to reduce anaesthetic side effects in non-domestic ruminants immobilised with medetomidine–tiletamine–zolazepam.

Comparison of the efficacy of four drug combinations for immobilization of wild pigs

Field immobilization of native or invasive wild pigs (Sus scrofa) is challenging. Drug combinations commonly used often result in unsatisfactory immobilization, poor recovery, and adverse side effects, leading to unsafe handling conditions for both animals and humans. We compared four chemical immobilization combinations, medetomidine–midazolam–butorphanol (MMB), butorphanol–azaperone–medetomidine (BAM™), nalbuphine–medetomidine–azaperone (NalMed-A), and tiletamine–zolazepam–xylazine (TZX), to determine which drug combinations might provide better chemical immobilization of wild pigs. We achieved adequate immobilization with no post-recovery morbidity with MMB. Adequate immobilization was achieved with BAM™; however, we observed post-recovery morbidity. Both MMB and BAM™ produced more optimal results relative to body temperature, recovery, and post-recovery morbidity and mortality compared to TZX. Adequate immobilization was not achieved with NalMed-A. Of the four drug combinations examined, we conclude that MMB performed most optimally for immobilization and recovery of wild pigs.

Comparison between total intravenous anesthesia with propofol and intermittent bolus of tiletamine-zolazepam in capuchin monkey (Sapajus apella)

ABSTRACT: Dissociative anesthesia results in stressful and long recovery periods in monkeys and use of injectable anesthetics in medical research has to be refined. Propofol has promoted more pleasure wake up from anesthesia. The objectives of this study were to investigate the use of intravenous anesthetic propofol, establishing the required infusion rate to maintain surgical anesthetic level and comparing it to tiletamine-zolazepam anesthesia in Sapajus apella. Eight healthy capuchin monkeys, premedicated with midazolam and meperidine, were anesthetized with propofol (PRO) or tiletamine-zolazepam (TZ) during 60 minutes. Propofol was infused continually and rate was titrated to effect and tiletamine-zolazepam was given at 5mg/kg IV bolus initially and repeated at 2.5mg/kg IV bolus as required. Cardiopulmonary parameters, arterial blood gases, cortisol, lactate and quality and times to recovery were determined. Recovery quality was superior in PRO. Ventral recumbency (PRO = 43.0±21.4 vs TZ = 219.3±139.7 min) and normal ambulation (PRO = 93±27.1 vs TZ = 493.7±47.8 min) were faster in PRO (p&lt;0.05). Cardiopulmonary effects did not have marked differences between groups. Median for induction doses of propofol was 5.9mg/kg, varying from 4.7 to 6.7mg/kg, Mean infusion rate was 0.37±0.11mg/kg/min, varying during the one-hour period. In TZ, two animals required three and five extra doses. Compared to tiletamine-zolazepam, minor post-anesthetic adverse events should be expected with propofol anesthesia due to the faster and superior anesthetic recovery.

Anesthetic quality and cardiovascular and respiratory effects of continuous intravenous infusion of tiletamine-zolazepam in bitches

ABSTRACT: The objective of this study was to evaluate the quality and recovery from anesthesia promoted by the tiletamine-zolazepam (TZ) combination administered intravenously (IV) continuously in bitches pre-medicated with acepromazine. Eight cross-bred, clinically healthy bitches weighing 13.7 ±1.9kg on average were used in this study. After a food fast of 12 h and a water fast of four hours, the animals were treated with acepromazine (0.1mg/kg, intramuscular) and, after 15 minutes, anesthesia was induced with a combination of tiletamine-zolazepam (2mg/kg, IV) immediately followed by continuous IV infusion thereof at a dose of 2mg/kg/h for 60 min. The following parameters were measured in all animals immediately before administration of acepromazine (M15), immediately before anesthetic induction (M0), and at 5, 10, 20, 30, 40, 50, and 60 min after initiation of continuous infusion (M5, M10, M20, M30, M40, M50, and M60): electrocardiography (ECG), heart rate (HR), mean arterial pressure (MAP), respiratory rate (RR), body temperature (BT), and arterial hemogasometry, with the last performed only at experimental times M15, M0, M30, and M60. A subcutaneous electrical stimulator was used to evaluate the degree of analgesia. Myorelaxation and quality of anesthetic recovery were also assessed, classifying these parameters as excellent, good, and poor. Anesthetic recovery time was recorded in minutes. HR increased significantly at time M10 in relation to that at M-15, and at times M5, M10, M40, and M50 in relation to that at M0. MAP decreased significantly at M20 and M30 compared with the baseline. BT decreased significantly at M50 compared with that at M0, but no hypothermia was observed. RR showed significant reduction at M5, M10, and M20 in relation to that at M-15, and at M5 and M10 in relation to that at M0, and bradypnoea was observed during the first 20 min after anesthetic induction. Significant decreases in the PR interval at times M10, M40, and M50 were observed in relation to that at M15. Amplitude of the R wave showed significant decrease at M20 compared with that at M-15. In the other ECG parameters, no significant difference was observed between the times evaluated. Hemogasometric parameters and analgesia did not show significant alterations. Myorelaxation and quality of anesthetic recovery were considered excellent. Recovery time was 15.1±7.7 min for positioning of sternal decubitus and 45.5±23.1 minutes for return of ambulation. Continuous IV administration of TZ combination does not produce satisfactory analgesia and does not cause severe cardiorespiratory and hemogasometric effects in bitches pre-medicated with acepromazine.