Duration Of Licking Research Articles

Protective Effects of a Polyherbal Formulation, Freemodex, Against Acute Models of Pain, Inflammation, Arthritis, and Immunosuppression

Aim: This study was designed to evaluate the analgesic, anti-inflammatory, antiarthritic and immunomodulatory activities of Freemodex. Materials and Methods: Acute models of pain – formalin-induced paw licking, inflammation – egg albumin induced paw edema, arthritis – turpentine-induced arthritis, and immunosuppression – carbon clearance test and cyclophosphamide-induced neutropenia were evaluated using rats and mice. The degree of protection was determined for antiarthritic, analgesic, and anti-inflammatory activities by measuring the paw volume, percentage inhibition, the number of writhing movements, the duration of paw licking in the injected paw, paw linear circumference, and the joint diameter. The estimation of phagocytic index, the total leukocyte count, and the percentage reduction in the neutrophil count were indexed for the evaluation of immunosuppression. Freemodex was administered at 40 and 80 mg/kg to rats and 80 and 160 mg/kg to mice. Results: Dose-dependent reduction in paw licking was observed in the formalin model. Reduction in paw volume was seen in the animals treated with egg albumin and Freemodex. Arthritis was also found to be decreased on the basis of the synovial joint size and phagocytic index. Leukocytes and neutrophils were also normalized in mice. Conclusion: The study’s findings suggest a protective role for Freemodex.

Synthesis and antinociceptive activities of some novel benzimidazole-piperidine derivatives

In this study, a series of benzimidazole-piperidine derivatives were synthesized with the objective of developing potent antinociceptive agents. Some 2-(4-substituted-phenyl)-1-[2-(piperidin-1-yl)ethyl]-1$H$-benzimidazole derivatives were obtained by microwave-supported reaction of an appropriate 2-(4-substituted-phenyl)-1$H$-benzimidazole with 2-(piperidine-1-yl)ethyl chloride. The chemical structures of the compounds were elucidated by FT-IR, $^{1}$H NMR, $^{13}$C NMR, and HRMS spectral data. Antinociceptive activity was assessed by conducting hot-plate, paw-pressure, and formalin tests. Morphine (5 mg/kg, i.p) was used as a reference drug. Among the tested compounds 2a-2d and 2f-2h (10 mg/kg) increased the maximum possible effect (MPE) % values calculated for the hot-plate and paw-pressure tests and decreased the paw licking time of rats in the early phase of the formalin test, indicating centrally mediated antinociceptive activities of these derivatives. In the late-phase 2g and 2h were the only compounds reducing the paw licking duration. These data show additional peripherally mediated antinociceptive activities for these two derivatives. Falling latencies of animals in the rotarod test did not change upon the administration of test compounds; thus, the observed antinociceptive effects were specific. Predictions obtained by theoretical calculations of ADME (absorption, distribution, metabolism, excretion) properties supported the antinociceptive potential of the tested benzimidazole-piperidine derivatives.

Vitamin B12 and ketorolac on pain in Long Evans rats

Background: Effects of vitamin B12 on pain have been demonstrated in different animal and human studies. But comparison of these effects with similar effects of ketorolac tromethamine (KT) and their combination have not been established.Objective: To assess the effects of vitamin B12 on pain and also to compare them with those of the combinations of vitamin B12 with KT in rat models.Methods: This experimental study was conducted in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, from March 2015 to February 2016. For this, 20 (twenty) Long Evans rats (215±35 gm) of both sexes were divided into control (A, with 5 ml/kg normal saline) and experimental (B1, with 15 mg/kg B12; B2, with 10 mg/kg KT; B3, with B12+KT) groups with 5 rats in each group. All the drugs and vitamin were administered intraperitoneally in a single dose just one hour before formalin test. To evaluate the treatments’ effect on nociceptive pain, early phase (1st- 5th minutes); on central analgesic system, interphase (6th-15th minutes); and on inflammatory pain, late phase (16th-60th minutes) of the formalin test, were observed. In all phases, total frequency of jerking and total duration of flexing and licking of the right hind paw were counted after administration of subcutaneous formalin (50 ?l, 2.5%) injection. Statistical analysis was done by ANOVA, followed by Bonferroni post hoc test. In the interpretation of results, p?0.05 was considered as significant.Results: B12 lowered only the jerking frequency and KT lowered both jerking frequency and flexinglicking duration significantly (p?0.001) in the late phase of formalin test. On the other hand, combination of B12 and KT significantly (p?0.001) lowered both the study variables in all 3 phases of formalin test.Conclusion: From this study it may be concluded that, vitamin B12 possess analgesic effects and combination of B12 with KT is more effective than those of their individual administration.Bangladesh Soc Physiol. 2016, December; 11(2): 63-69

Antinociceptive and anti-inflammatory effects of thiamine in Long Evans rats

Background: Thiamine along with other B vitamins has been prescribed since long for treatment of various painful conditions, though individual effects of thiamine on nociception and inflammation are yet to be clearly demonstrated.Objective: To assess the effects of increasing doses of thiamine supplementation against pain and inflammation.Methods: This experimental study was conducted in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka from March 2014 to February 2015. Total twenty four male Long Evans rats weighing (200±20 gm) were treated with three different doses of thiamine hydrochloride (THCL 100, 200, 250, mg/kg/day; experimental) or normal saline (5 ml/kg/day; control) intraperitoneally for 7 consecutive days. To evaluate the thiamine’s effect on nociceptive pain, early phase (0-5 minutes) and on inflammatory pain, late phase (16-60 minutes) of the formalin test, were observed. In both phases, total frequency of jerking and total duration of flexing and licking of the right hind paw were counted after administration of subcutaneous formalin (50 ?l, 2.5%) injection. After formalin test, all the rats were also subjected to formalin induced paw edema test using a water plethysmometer to observe the antiinflammatory effect of thiamine. Statistical analysis was done by ANOVA, followed by Bonferroni post hoc test. In the interpretation of results, p?0.05 was considered as significant.Results: In formalin test, thiamine lowered frequency of jerking (after all 3 doses, in both phases) and duration of flexing and licking (200 mg/kg - p<0.001, in late phases; 250 mg/kg (p<0.001), in both phases) significantly. Additionally, thiamine lowered paw edema significantly (p<0.001) in higher 2 doses.Conclusion: This study concludes that, thiamine may have dose dependent antinociceptive and anti-inflammatory effects.Bangladesh Soc Physiol. 2016, June; 11(1): 6-12

Effects of neonatal pain, stress and their interrelation on pain sensitivity in later life in male rats.

Neonatal pain and stress induce long-term changes in pain sensitivity. Therefore their interrelation is a topical subject of clinical and basic research. The present study investigated the effects of inflammatory peripheral pain and stress of maternal deprivation (MD)-isolation in 1-2- and 7-8-day-old Wistar rats (P1,2 and P7,8 respectively, ages comparable to preterm and full-term human babies) on basal pain and pain sensitivity in conditions of inflammatory pain (formalin test) during adolescence. The neonatal impacts were: pain (formalin injection, FOR in the paw), stress (a short 60-min MD), or pain+stress combination (FOR+MD), and appropriate controls. We found that stress of short-term maternal deprivation-isolation and inflammatory pain on P1,2 and P7,8 significantly increased the vulnerability of the nociceptive system to inflammatory pain. Maternal deprivation-isolation on P1,2 as compared with a similar impact on P7,8 had a greater effect on pain sensitivity of the adolescent rats, but the influence of early pain was independent of the injury age. Only adolescent rats with an early combination of pain and maternal deprivation-isolation showed hypoalgesia in the hot plate (HP) test. However licking duration (reflecting pain sensitivity) in these rats did not exceed licking duration in animals exposed only to maternal deprivation-isolation or pain. This study adds new data to the growing body of work demonstrating that early noxious impacts have long-term consequences for the functional activity of the nociceptive system. Our new findings may help to understand the impact of pain and maternal separation in the neonatal intensive care unit.

Anti-inflammatory and antinociceptive activities of Croton urucurana Baillon bark

Ethnopharmacological relevanceCroton urucurana (Euphorbiaceae) is popularly used in Brazil to treat inflammatory processes, pain, and gastric ulcers. Aim of studyTo evaluate the anti-inflammatory and antinociceptive properties of the methanol extract from the bark of C. urucurana (MECu) in mice and identify its chemical constituents. Materials and methodsThe extract was characterized by UHPLC-DAD-ESI-Q-TOF-MS/MS. Extract doses of 25, 100, and 400mg/kg were employed in the biological assays. Evaluation of anti-inflammatory activity was based on paw edema and leukocyte recruitment into the peritoneal cavity of mice, both induced by carrageenan. Abdominal writhing caused by acetic acid and duration of formalin-induced paw-licking were the models employed to evaluate antinociceptive activity. ResultsTen compounds were identified in the extract: (+)-gallocatechin (1), procyanidin B3 (2), (+)-catechin (3), (−)-epicatechin (4), tembetarine (5), magnoflorine (6), taspine (7), methyl-3-oxo-12-epi-barbascoate (8), methyl-12-epi-barbascoate (9), and hardwickiic acid (10). This is the first report of compounds 2, 4, 6, 7, and 10 in C. urucurana and compound 5 in the genus Croton. In addition to inhibiting paw edema and leukocyte recruitment (particularly of polymorphonuclear cells) into the peritoneal cavity of mice, MECu reduced the number of abdominal writhings induced by acetic acid and the duration of formalin-induced paw licking. ConclusionsThe methanol extract of C. urucurana bark exhibited anti-inflammatory and antinociceptive properties, corroborating its use in folk medicine. These effects may be related to the presence of diterpenes, alkaloids, and flavonoids.

The Influence of a Soft Touch Therapy Flowtrition on Heart Rate, Surface Temperature, and Behavior in Horses

This study tested Flowtrition, a noninvasive soft touch therapy, on the mean and maximum heart rate (HRavg and HRmax, respectively), surface temperature in three body quadrants, and eight stress-related behaviors in horses. Fourteen gelded horses were randomly assigned to a control (CON, n = 5) group or a Flowtrition (treatment, TRT, n = 9) group. Each horse underwent four sessions with each session split into three 20-minute stages: Pre, During, and Post. At the end of the Pre stage in which neither group received any intervention, baseline heart rate, temperature, and behaviors were recorded. A During stage followed in which the TRT group received therapy, and the CON group was monitored and received no treatment. Within the Post period, both groups were monitored and response variables were recorded. The TRT group experienced a decrease (P < .05) of 10 ± 2.7 bpm in HRmax and 4.7 ± 0.8 bpm in HRavg between Pre and Post stages compared to the CON group, which experienced no shifts in heart rate. The group receiving therapy showed an increase (P < .05) in occurrence frequency and total duration of head lowering, licking and chewing, and yawning between Pre and Post stages; the CON group showed no behavioral shifts. The results show that Flowtrition induces a more relaxed state in horses as evidenced by a decrease in HR and increase in occurrence and duration of relaxation-related behaviors.

Elevated dopamine alters consummatory pattern generation and increases behavioral variability during learning.

The role of dopamine in controlling behavior remains poorly understood. In this study we examined licking behavior in an established hyperdopaminergic mouse model—dopamine transporter knockout (DAT KO) mice. DAT KO mice showed higher rates of licking, which is due to increased perseveration of licking in a bout. By contrast, they showed increased individual lick durations, and reduced inter-lick intervals. During extinction, both KO and control mice transiently increased variability in lick pattern generation while reducing licking rate, yet they showed very different behavioral patterns. Control mice gradually increased lick duration as well as variability. By contrast, DAT KO mice exhibited more immediate (within 10 licks) adjustments—an immediate increase in lick duration variability, as well as more rapid extinction. These results suggest that the level of dopamine can modulate the persistence and pattern generation of a highly stereotyped consummatory behavior like licking, as well as new learning in response to changes in environmental feedback. Increased dopamine in DAT KO mice not only increased perseveration of bouts and individual lick duration, but also increased the behavioral variability in response to the extinction contingency and the rate of extinction.

Gender differences in a mouse model of chemotherapy-induced neuropathic pain.

Chemotherapy-induced neuropathic pain is one of the major problems for cancer patients. Although paclitaxel and cisplatin are widely used in women, most laboratory studies of chemotherapy-induced neuropathic pain have been conducted on male animals. The current study examined the gender differences in chemotherapy-induced neuropathic pain in mice. Neuropathic pain was induced by intraperitoneal injection of paclitaxel (2 mg/kg) for five consecutive days and cisplatin (1 mg/kg) for seven consecutive days. Cold allodynia was evaluated by measuring the paw withdrawal frequency and duration of paw licking in mice; however, mechanical allodynia was assessed by von Frey filaments. Neuropathic pain began to manifest after a few days (P < 0.001). Cold allodynia was more robust in female mice (P < 0.001) treated with paclitaxel, while no differences were observed between the two genders in the manifestation of paclitaxel-induced mechanical allodynia. Interestingly, no gender differences were observed in cisplatin-induced cold and mechanical allodynia tests. In conclusion, gender differences play a major role in neuropathic pain induced by paclitaxel. The differences between male and female animals should be considered in future studies and the findings should be generalized to humans with caution.

Heat hyperalgesia and mechanical hypersensitivity induced by calcitonin gene-related peptide in a mouse model of neurofibromatosis.

This study examined whether mice with a deficiency of neurofibromin, a Ras GTPase activating protein, exhibit a nociceptive phenotype and probed a possible contribution by calcitonin gene-related peptide. In the absence of inflammation, Nf1+/− mice (B6.129S6 Nf1<tm1Fcr>/J) and wild type littermates responded comparably to heat or mechanical stimuli, except for a subtle enhanced mechanical sensitivity in female Nf1+/− mice. Nociceptive phenotype was also examined after inflammation induced by capsaicin and formalin, which release endogenous calcitonin gene-related peptide. Intraplantar injection of capsaicin evoked comparable heat hyperalgesia and mechanical hypersensitivity in Nf1+/− and wild type mice of both genders. Formalin injection caused a similar duration of licking in male Nf1+/− and wild type mice. Female Nf1+/− mice licked less than wild type mice, but displayed other nociceptive behaviors. In contrast, intraplantar injection of CGRP caused greater heat hyperalgesia in Nf1+/− mice of both genders compared to wild type mice. Male Nf1+/− mice also exhibited greater mechanical hypersensitivity; however, female Nf1+/− mice exhibited less mechanical hypersensitivity than their wild type littermates. Transcripts for calcitonin gene-related peptide were similar in the dorsal root ganglia of both genotypes and genders. Transcripts for receptor activity-modifying protein-1, which is rate-limiting for the calcitonin gene-related peptide receptor, in the spinal cord were comparable for both genotypes and genders. The increased responsiveness to intraplantar calcitonin gene-related peptide suggests that the peripheral actions of calcitonin gene-related peptide are enhanced as a result of the neurofibromin deficit. The analgesic efficacy of calcitonin gene-related peptide receptor antagonists may therefore merit investigation in neurofibromatosis patients.

English

&nbsp; Due to low side effects and costs as well as proper adaptation to body&rsquo;s physiology, there is a global trend in using herbal medications. To investigate the analgesic effects of Arum maculatum plant extract in rats via an experimental study, 60 healthy male Wistar rats were divided into 6 equal groups including 3 plant extract groups, a negative control with normal saline and 2 positive control groups with morphine and diclofenac Na injections. Morphine, diclofenac or different dosages of extract were injected subcutaneously into the left sole of rats via insulin syringes. Two hundred microliters of 1% formalin were then subcutaneously injected into the left paw of each rat for pain induction. The duration of the left paw licking was measured just after formalin injection (phase I) and 20 min after the injection (phase II). Finally, the mean duration of paw licks was compared between treatment and control groups. The shortest duration of licks was found in the morphine injected group (30.6 &plusmn;1.9 and 37.2&plusmn;1.1 seconds at phase I and II, respectively). Compared to diclofenac injection, plant extract of 500 and 750 mg/kg reduced the licks duration significantly during both phases (p&lt;0.0001). The lick durations, after the injection of 500 and 750 mg/kg extracts, were almost the same as that in the morphine injected group during phase I, but took longer during phase II. Rats in the 750 mg/kg extract injected group, compared to those in the 500 mg/kg extract injected group, showed a significantly shorter lick duration during phase II (p&lt;0.0001), but not phase I (p=0.708). Following further investigations in human, A. maculatum plant extract can be introduced as a natural and better analgesic substitution for diclofenac Na which has the same effect as morphine during phase I.&nbsp;&nbsp; &nbsp; Key words:&nbsp; Arum maculatum, morphine, diclofenac Na, formalin, Iran.

Activation of GABAA and GABAB receptors in the lateral septum increases sucrose intake by differential stimulation of sucrose licking activity

The present study was aimed to determine how direct injections into the lateral septum (LS) of muscimol and baclofen, GABAA and GABAB receptor agonists, respectively, affect intake of 10% sucrose and sucrose licking activity in rats. The effects of muscimol and baclofen on the 1-h intake of sucrose and sucrose licking activity were tested at low (350pmol), medium (876pmol), and high (1752pmol) doses. The medium and high doses of muscimol and the high dose of baclofen significantly increased 1-h sucrose intake. The total sucrose lick number was significantly increased by the medium dose of muscimol and the high dose of baclofen. An increase in sucrose licking activity induced by muscimol but not baclofen occurred in the first 15min after injections. The medium and high doses of muscimol but not baclofen significantly decreased latency to initiate the first lick of sucrose. The total licking time calculated as the sum of the duration of all sucrose lick clusters showed a significant increase by the high dose of baclofen but not by any dose of muscimol. Therefore, the GABAA and GABAB LS mechanisms appear to be involved in stimulating sucrose intake, but this stimulation occurs by differential regulation of the sucrose licking activity. Muscimol intra-LS administration led to a short-latency rapid increase in sucrose licking. In contrast, baclofen did not decrease latency to initiate licking, but significantly increased total licking duration.

Sulfated polysaccharides isolated from the green seaweed Caulerpa racemosa plays antinociceptive and anti-inflammatory activities in a way dependent on HO-1 pathway activation

Marine algae are abundant sources of sulfated polysaccharides with various biological activities. Consequently, their biomolecules are of great of commercial interest. In this study, we investigated the potential antinociceptive activity of a sulfated polysaccharide obtained from the green seaweed Caulerpa racemosa (CrII) and the involvement of the hemoxigenase-1 (HO-1) pathway in its anti-inflammatory effect. We used a systemic evaluation to verify possible toxic effects of Crll after consecutive treatments. Swiss mice and Wistar rats were used for all experiments. In Swiss mice, CrII (0.01, 0.1 and 1.0 mg/kg) significantly reduced the number of abdominal contortions and the duration of paw licking in the second phase after treatment with acetic acid and formalin, respectively. However, CrII was unable to prolong the reaction time of thermally stimulated animals. The anti-inflammatory effect of CrII (0.01, 0.1 and 1.0 mg/kg) was evidenced by a decreased number of leukocytes in the peritoneal cavities of the rats. CrII (0.01, 0.1 and 1.0 mg/kg) also reduced the amount of paw edema induced by carrageenan (Cg) and dextran. The anti-inflammatory effect of CrII was confirmed by reduced levels of myeloperoxidase in the paw tissue of the Cg groups. After inhibition with ZnPP IX, a specific HO-1 phenotype inhibitor, the anti-inflammatory effect of CrII was no longer observed in Cg-induced paw edema tests. Consecutive Crll (1.0 mg/kg) for 14 days did not change any biochemical or histopathological parameters, or cause mortality of mice. CrII did not produce any signs of toxicity and effectively decreased nociception and inflammation. Also, the anti-inflammatory effect of Crll is at least in part dependent on the integrity of the HO-1 pathway.

Pharmacological evaluation of the analgesic and anxiolytic activities of Jobelyn® in mice.

Abstract Background: This study presents the results of the pharmacological evaluation of the analgesic and anxiolytic potentials of Jobelyn®, a potent antioxidant African herbal formulation, in mice. The analgesic effect was assessed utilizing acetic acid-induced writhing, tail immersion and formalin-induced paw licking pain models. The anxiolytic activity was evaluated using elevated-plus maze (EPM) and light/dark box. Methods: Mice (5/group) were treated with JB (10-200 mg/kg, p.o.) 1 h before the tests were carried out. In the writhing test, the number of abdominal constrictions was recorded for a period of 30 min after induction of nociception with 0.6% acetic acid, i.p. In the tail immersion test, the latency to tail withdrawal responses to noxious heat was measured. The duration of paw licking (s) was measured as an index of nociception in the formalin test. In the anxiolytic test, the patterns of transition in the two arms of the EPM and in the light/dark box were assessed. Results: JB (10-200 mg/kg, p.o.) significantly inhibited the inflammatory pain produced by acetic acid as evidenced by decreased number of abdominal constrictions in comparison with the control. It also shows higher potency in suppressing the inflammatory pain associated with the second phase of the formalin test. However, JB did not exhibit anxiolytic properties nor modify the pain behavior in the tail immersion test. Conclusions: The results obtained from this study suggest that Jobelyn® might be efficacious against inflammatory pain and further support its recommendation for the management of pain with inflammation as the underlying factor.

Parental behaviour of prairie voles (Microtus ochrogaster) and meadow voles (M. pennsylvanicus) in relation to sex of offspring

Monogamous parents are predicted to invest equally in male and female offspring whereas polygynous parents in good condition are predicted to invest more in male than female offspring. Sex-biased parental investment can occur in three ways: (1) mothers and fathers invest different amounts of care in their offspring (effect of parent sex); (2) parents invest different amounts of care in male and female offspring (effect of offspring sex); and (3) one parent, but not the other, invests different amounts of care in male and female offspring (interaction between parent sex and offspring sex). Studies of parent–offspring interactions in rodents have focused on either effect of parent sex or effect of offspring sex, but not the interaction between parent sex and offspring sex, and most studies have examined only one species. We studied prairie voles (Microtus ochrogaster), a monogamous species, and meadow voles (M. pennsylvanicus), a polygynous (or promiscuous) species, under laboratory conditions designed to simulate field conditions. For each species, we recorded the frequency and duration with which mothers and fathers licked their male and female offspring. We found that meadow vole fathers licked male offspring for longer durations than female offspring. However, prairie vole fathers, prairie vole mothers, and meadow vole mothers did not lick male and female pups for different durations. From the standpoint of the pups, male prairie vole pups, female prairie vole pups, and female meadow vole pups were licked for longer durations by their mothers than by their fathers. In contrast, for male meadow vole pups there was no difference in the duration with which they were licked by mothers and fathers. We also detected effects of litter size: as litter size increased, the frequency and duration of pup licking decreased for mothers and increased for fathers. For duration (but not frequency) of pup licking, these changes were more dramatic in meadow voles than in prairie voles. Our data are generally consistent with predictions that monogamous parents, such as prairie voles, should invest equally in male and female offspring whereas polygynous (or promiscuous) parents, such as meadow voles, should invest more in male offspring when conditions are favourable. Our data also highlight the complexity of parent–offspring interactions in rodents and emphasize the need to examine whether male and female offspring within a species differ in their behaviour or ability to obtain parental care.

Effects of Unsaturated Fatty Acid Esters of Testosterone on Neuronal, Behavioral and Hormonal Parameters in Male Rats Subjected to the Formalin Test

Chronic diseases are often accompanied by inflammatory and degenerative processes. Estrogens have repeatedly been found to be involved in these processes. Testosterone (T) is the main precursor of estrogen in the brain and T replacement in chronic diseases has become important in recent years, prompting research on new T-conjugated molecules. We recently synthesized three new molecules including unsaturated fatty acid esters: T-linoleate (TL), T-oleate (TO) and T-eicosapentanoate (TEPA). These substances were s.c. administered for 7 days to intact male rats subjected to the formalin test (FT). Three other groups were included as comparisons: NAIVE, receiving no substance, OIL, treated with almond oil (vehicle), and TN, treated with T-undecanoate, a saturated fatty acid. Spontaneous behaviors and pain-induced responses were determined during the FT, hormones (T and dihydrotestosterone, DHT) were determined in blood, while estrogen receptors (ERα and β) were detected at the genomic and proteomic levels in the hippocampus, hypothalamus and spinal cord. In the hippocampus, ERα and ERβ mRNA levels were increased respectively by TN and TL treatments with respect to OIL, whereas the hypothalamus TO and TL caused a decrease of ERα mRNA levels. At the proteomic level, TO, TL and TEPA decreased the levels of ERα in the hypothalamus, whereas TEPA decreased ERβ in the spinal cord, hippocampus and hypothalamus. There was no effect of treatment on the spontaneous behaviors, while the TO and TL groups showed lower pain-induced behaviors (paw jerk frequency and licking duration) than the OIL group. TN increased paw jerk frequency and decreased licking duration with respect to OIL. The treatments had no effect on T and DHT plasma levels. These results clearly indicate the possibility of pain and ER modulation by T-esters.

Comparative Effect of Cannabis, Aspirin and Cataflam on Nociception in Cd1 Mice

The effects of cataflam, aspirin and the ethanolic extract of Cannabis sativa on nociception was studied in albino mice of both sexes. Forty (40) albino mice were divided into four (4) groups of ten (10) each. The control group was given normal saline (p.o). Test group one (1) was given (p.o) cataflam at a dose of 1.5mg/kg. Test group two (2) was given (p.o) aspirin at a dose of 13.5mg/kg. Test group three (3) was given the ethanolic extract of Cannabis sativa at a dose of 10mg/kg. All four (4) groups were given access to normal mice chow and water ad libitum. The hot plate test was used to assess the effects of the test substances on sensitivity to acute thermal pain while the formalin test was used to assess the sensitivity to persistent pain due to peripheral tissue injury and inflammation. The result shows that Cannabis, Cataflam and Aspirin all reduce sensitivity to pain. This is indicated by the reduction in frequency and duration of hind paw licking in both phases of the formalin test (p<0.05). Cataflam and Cannabis may not have any effect on sensitivity to acute thermal pain. There was no significant difference in the latency of jump in the groups treated with Cataflam and Cannabis during the hot plate test compared to control (p<0.05). But they all reduce sensitivity to persistent inflammatory pain.

Relationships between ectoparasites and grooming behavior of Tylonycteris pachypus and T. robustula

Grooming behavior is evolved in animals in response to the costs associated with ectoparasites. In this study, ecotparasite densities and grooming behavior-including licking and scratching-of wild-caught lesser bamboo bat (Tylonycteris pachypus) and greater bamboo bat (T. robustula) were analyzed. The results indicated that both the frequencies and durations of licking were higher than those of scratching in both bat species, though T. pachypus licked more but scratched less than T. robustula. There were no difference in the durations of licking and scratching between the two bat species, and the durations and frequencies of grooming behavior of the two bat species were irrelevant with ectoparasite densities. These findings suggest that the grooming behavior of T. pachypus and T. robustula might be modulated by both the central control (programmed grooming) model and the peripheral stimulation (stimulus driven) model.

Sensitivity to temporal reward structure in amygdala neurons.

SummaryThe time of reward and the temporal structure of reward occurrence fundamentally influence behavioral reinforcement and decision processes [1–11]. However, despite knowledge about timing in sensory and motor systems [12–17], we know little about temporal mechanisms of neuronal reward processing. In this experiment, visual stimuli predicted different instantaneous probabilities of reward occurrence that resulted in specific temporal reward structures. Licking behavior demonstrated that the animals had developed expectations for the time of reward that reflected the instantaneous reward probabilities. Neurons in the amygdala, a major component of the brain's reward system [18–29], showed two types of reward signal, both of which were sensitive to the expected time of reward. First, the time courses of anticipatory activity preceding reward delivery followed the specific instantaneous reward probabilities and thus paralleled the temporal reward structures. Second, the magnitudes of responses following reward delivery covaried with the instantaneous reward probabilities, reflecting the influence of temporal reward structures at the moment of reward delivery. In being sensitive to temporal reward structure, the reward signals of amygdala neurons reflected the temporally specific expectations of reward. The data demonstrate an active involvement of amygdala neurons in timing processes that are crucial for reward function.

Evaluation of analgesic activity of the leaves of Passiflora incarnata Linn

Passiflora incarnata also known as ‘Passion flower’ is used as an anxiolytic and sedative throughout the world from ancient time. The plant is used as an analgesic, antispasmodic, sedative- hypnotic and narcotic. It is also used in neuralgia, epilepsy, insomnia, ulcers, haemorrhoids and neurosis in many parts of the world. There was no report on analgesic activity of P. incarnata. Hence, the present study is designed to assess analgesic activity of leaves of P. incarnata using sodium chloride-induced eye wiping test and formalin test. In formalin test, n-butanol extract of leaves of P. incarnata (BEPI) in the doses of 150 and 300 mg/kg as well as BEPI-F1 showed significant reduction in duration of paw licking in neurogenic and inflammatory phase(P<0.001). Pretreatment with naloxone reversed the analgesia induced by BEPI, while atropine did not reverse the analgesia induced by BEPI significantly (P≤0.001). In eye wiping test, BEPI in the doses of 150 and 300 mg/kg, i.p. exerted significant reduction (P≤0.001) in number of eye wipes compared to control group. Thus, the result concludes that BEPI and the fraction separated, BEPI–F1 has significant analgesic activity, which may be mediated through central mechanism by modulation of opioid receptors and nicotinic receptors. Key words: Analgesic activity, eye wiping test, Passiflora incarnata, trigeminal neuralgia