Basal Cardiovascular Parameters Research Articles

Association of Neck Circumference with Body Composition and Cardiovascular Parameters in Young Healthy Adult Males

Background and Aim: Increased Neck circumference is the marker of upper body obesity and identified as an indicator of future cardiovascular disease risk (CVD). Hence, in this study, we assessed the relationship of Neck circumference (NC) with basal cardiovascular and body composition (BC) parameter in young adult males. Methods: Sixty three healthy young adult male volunteers of age between 18 to 25 years were enrolled for this study and they were divided into two groups based on neck circumference (NC). Control group (n = 32) comprises of individuals with normal neck circumference of ≤ 35.5 cm and study group (n = 31) includes individuals with increased neck circumference of ≥ 35.5 cm. The, BC parameters was assessed by Bioimpedance Analysis (BIA) method using Quadscan 4000. And the basal cardiovascular parameters such as systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR) was measured by automated sphygmomanometer and the pulse pressure (PP), mean arterial pressure (MAP) and the rate pressure product (RPP) were derived. Results: Data was expressed in Mean ± SD. The groups were compared using Independent Student’s t test. The association between NC and various study parameters were assessed by Pearson’s correlation analysis. Our study, revealed increased body fat and reduced muscle mass in individuals with increased NC. Further, we observed a positive correlation of NC with body fat (%) and negative correlation with Lean Body Mass. Cardiovascular parameters SBP, DBP, MAP and PP were elevated in subjects with increased NC. Further, positive correlation is seen with SBP, DBP, RPP and NC. Conclusion: Neck circumference is a readily measurable screening tool of upper-body adiposity and increased NC is associated with CVD risk.

Assessment of Cardiovascular Risk in People Living with Epilepsy

Background and Aim: Increase prevalence of cardiovascular morbidity and mortality has been reported in people living with epilepsy (PWE) compared to the general population. This study was done to assess the cardiovascular risk of PWE using Heart rate variability (HRV) and Blood Pressure variability (BPV) techniques. Methods: Twenty-seven patients with epilepsy and thirty age and gender-matched healthy individuals were included in the study and control group, respectively. Basal cardiovascular parameters (heart rate-HR, systolic blood pressure- SBP, diastolic blood pressure-DBP), HRV indices, and BPV parameters were recorded and compared between the study and control group individuals. In addition, the association of the Total Power (TP) of HRV with other study parameters was assessed by Pearson correlation coefficient test. Results: Cardiovascular parameters such as HR, SBP, DBP, rate pressure product, cardiac output and total peripheral resistance were significantly high in PWE compared to healthy individuals. Baroreflex sensitivity (BRS) and HRV parameters indicative of cardiac parasympathetic drive (TP, SDNN, RMSSD, and pNN50) were significantly low in these individuals. While a significant negative correlation was observed between TP, BHR and DBP, a significant positive correlation was observed between TP and BRS. Conclusion: Cardiac sympathovagal imbalance characterized by increased sympathetic and decreased parasympathetic activity was evident in PWE. These changes in the autonomic nervous system could predispose them to increased risk of cardiovascular morbidity.

Assessment of burden of internet addiction and its association with quality of sleep and cardiovascular autonomic function in undergraduate medical students

Problem consideredThis study aimed to determine the association of internet addiction with poor sleep quality and autonomic function in medical students. MethodsIn this cross-sectional study design, we assessed internet addiction, sleep quality, demographic and basal cardiovascular parameters (blood pressure and heart rate), autonomic indices (E: I ratio and isometric handgrip test (ΔDBPihg) in 148 medical students. Sleep quality and internet usage were assessed using questionnaires. Qualitative data were expressed in number (percentage) and analyzed using the Chi-square test. Normally distributed quantitative data were analyzed using student t-test and expressed as mean and SD. Logistic regression analysis was done to determine the association between sleep quality and internet addiction. p-value of <0.05 was considered to be significant. ResultsIn the present study, 64.9% of participants reported moderate internet usage, and 19.6% reported excessive internet usage. The preference for internet usage at night-time was more than daytime. Further, the internet addicted group demonstrated increased resting heart rate. We also observed a significant association between internet addiction and sleep quality. ConclusionThese findings of the present study show that internet overuse is associated with poor sleep quality in undergraduate medical students.

Effect of Standardized Hydroalcoholic Extract of Saffron Stamen on High Blood Pressure and Baroreflex Sensitivity in Anesthetized Rats.

The stamen is a byproduct of saffron (Crocus sativus) flowers. Herein, its cardiovascular effects were evaluated on hypertension induced by angiotensin II (AngII) and NG-nitro-Larginine methyl ester (L-NAME), as well as baroreflex sensitivity (BRS). Rats were randomly divided into 10 groups: 1) control, 2) AngII (50 ng/kg, i.v.), 3) losartan (10 mg/kg, i.p.) + AngII, 4) L-NAME (10 mg/kg, i.v.), 5) sodium nitroprusside (SNP) (50 mg/kg, i.p.) + L-NAME, 6, 7) saffron stamen extract (SS) (100 and 200 mg/kg, i.p.) + AngII and 8, 9) SS (100 and 200 mg/kg) + L-NAME, and 10) SS (200 mg/kg) + phenylephrine (Phen, i.v.). The treated rats first received two doses of SS, 30 min after the injection of L-NAME, AngII, and Phen in separate groups. The cardiovascular parameters were recorded by the PowerLab apparatus via an angiocatheter inserted into the femoral artery. The maximal changes (Δ) of mean arterial pressure (MAP), systolic blood pressure (SBP), and heart rate (HR) in the treated groups were compared with those of the hypertensive and control groups. The changes in MAP and HR induced by Phen were used for BRS evaluation. The SS extract did not significantly affect the basal cardiovascular parameters. The injection of AngII significantly increased the MAP and SBP (P<0.01-P<0.001) with no significant effect on the HR. The SS extract significantly attenuated the pressor effect induced by AngII (P<0.001). Increased MAP and SBP induced by L-NAME (P<0.001) were also significantly attenuated by the SS extract (P<0.01). The effect of SS extract on L-NAME was significantly higher than that of AngII (P<0.05). Moreover, BRS was significantly improved by the SS extract. Our findings provide evidence that the SS extract has anti-hypertensive effects that are probably mediated by an inhibitory effect on AngII, increasing nitric oxide production, or improving baroreflex sensitivity.

Hypotensive Effect of Hydroalcoholic Ziziphus jujuba Extract on Normotensive Rats

Objective: Ziziphus jujuba (Z.J) is a medicinal plant with several properties such as antioxidant, antibacterial, hypnotic and wound healing activity. It also has lowering blood pressure effect and people use it to treat hypertension. In the present study, the effect of hydroalcoholic extract of Z.J on cardiovascular parameters in the normotensive rats was investigated. Methods: Animal groups include: 1) Sham, only cannulation of artery 2) saline, received saline for four weeks 3-5) Z.J groups (100, 200 and 400 mg/kg) that treated with Z.J via gavage for four weeks. In the experiment day (28th Day) femoral artery of all rats cannulated and Systolic Blood Pressure (SBP), Mean Atrial Pressure (MAP) and Heart Rate (HR) recorded by a power lab system. The weight of animal in all groups also was recorded in the beginning and the last day of experiment. Results: There was no significant difference in HR, SBP and MAP parameters between sham and control groups. The SBP and MAP in higher doses of Z.J (200 and 400 mg) significantly decreased compared to control group. The HR only in dose 200 mg of Z.J significantly decreased than the control group. Conclusion: The results of present study show that hydroalcoholic extract of Z.J has an inhibitory effect on basal cardiovascular parameters and its best effects have been shown in dose 200 mg/kg.

Delayed Visual Evoked Response is Linked to Vascular Endothelial Growth Factor and Autonomic Dysfunction in Type 2 Diabetes Mellitus

Aims: In this study, we aimed to assess the link between visual evoked potentials (VEP), angiogenic marker (VEGF) and autonomic function tests in type-2 diabetes mellitus (T2DM). Methods: Age-matched 86 male subjects (44 type-2 diabetics on treatment and 42 normal healthy volunteers) were recruited for this study. Body mass index (BMI), basal cardiovascular parameters, spectral analysis of heart rate variability (HRV), were assessed. Fasting blood glucose, insulin, HOMA-IR and VEGF were estimated. The independent association of the P100 latency of VEP with VEGF was determined by multiple regression analysis. Results: LF-HF ratio a marker of sympathovagal balance, increased significantly (p=0.0287) in diabetic group compared to the control group. Comparison of visual evoked potentials between controls and diabetic groups showed significant increase in latency of P100 of both the eyes (right eye p<0.0001, left eye p=0.0003) among the cases. There was significant increase (p=0.0091) in VEGF in diabetic subjects when compared to control. Also positive and significant correlation of P100 latency of VEP with VEGF is seen in diabetics. Conclusions: There is delayed latency of VEP and increased VEGF in type 2 diabetic people. The correlation between VEP and VEGF could indicate the probable role of angiogenesis leading to reduced integrity of the neural pathways in T2DM.

A study of heart rate variability among non-diabetic offspring of type 2 diabetic parents

Background: Type 2 diabetes mellitus is an inheritable condition that runs in families as a disorder of impaired glycemic control and its complications. Among the complications of diabetes, autonomic neuropathy contributes to the development of cardiovascular disease states besides diabetic vascular complications. Sympathovagal imbalance is reported to be observed among the non-diabetic first-degree relatives of diabetic population. Aims and Objectives: To assess the heart rate variability (HRV) parameters in non-diabetic normotensive offspring of diabetic parents and infer the impairment in sympathovagal balance in them by comparing with the HRV findings of non-diabetic offspring of non-diabetic parents. Materials and Methods: This cross-sectional observational study was conducted on 30 healthy non-diabetic, normotensive volunteers with parental history of Type 2 diabetes and 30 non-diabetic normotensive volunteers without parental history of diabetes. The volunteers were between the age of 17 and 25 years with normal body mass index and no health condition that could influence the cardiovascular health. The basal cardiovascular parameters and a 5 min lead II electrocardiogram for short-term HRV analysis were recorded to assess the sympathovagal balance. Results: The HRV analysis reveals a statistically significant increase in the sympathetic components and decreased parasympathetic components in the nondiabetic offspring of diabetic parents when compared to the non-diabetic offspring of non-diabetic parents. Conclusion: From our study, it could be observed that the non-diabetic offspring of diabetic parents have enhanced sympathetic activity and attenuated vagal activity even in their non-diabetic state, thus inferring an early onset of sympathovagal imbalance that could predispose them to hypertension and its sequel.

Effect of Modified Slow Breathing Exercise on Perceived Stress and Basal Cardiovascular Parameters.

Context:Different types of breathing exercises have varied effects on cardiovascular parameters and the stress levels in an individual.Aim:The aim of this study was to assess the effect of a modified form of isolated alternate nostril, slow breathing exercise on perceived stress, and cardiovascular parameters in young, male volunteers.Settings and Design:This was a randomized control study carried out at Advanced Centre for Yoga Therapy Education and Research, Department of Physiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry in 2014.Subjects and Methods:Hundred healthy male volunteers were randomized into control group, n = 50 and slow breathing group (study), n = 50. Slow breathing exercise training was given to study group for 30 min a day, 5 times/week for 12 weeks, under the supervision of certified yoga trainers. Perceived Stress Scale (PSS) using Cohen's questionnaire, anthropometric parameters such as body mass index (BMI), waist-hip ratio (WHR), and cardiovascular parameters such as heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were recorded at baseline and after 12 weeks. The control group did not receive any intervention. Slow breathing exercise training was provided for the study group. During the study period, one volunteer opted out of the study group due to personal reasons.Results:HR, SBP, DBP, and PSS decreased significantly (P < 0.05) in the study group following 12 weeks slow breathing exercise training, while no significant change (P > 0.05) was observed in BMI and WHR. There was no significant change in the control group.Conclusion:Twelve weeks of modified slow breathing exercise reduced perceived stress and improved the cardiovascular parameters. The above results indicate that our modified slow breathing exercise is effective in reducing stress and improving the cardiovascular parameters.

Assessment of heart rate variability and reaction time in traffic policemen

Introduction: Air Pollution can have a deleterious effect on cardiovascular function and cognition. Heart rate variability (HRV), which is a non-invasive and objective measure of cardiac autonomic function, is a cardiovascular risk predictor. Reaction time is a simple method of assessing the perceptual-cognitive processing capability of the central nervous system. Hence, the aim of the study was to assess the heart rate variability and reaction time in traffic police officers of Puducherry. Methods: Fifty-five age and BMI matched traffic police and healthy controls were recruited. Basal cardiovascular parameters; basal heart rate, systolic and diastolic blood pressure (BHR, SBP, DBP) were assessed. Short term HRV analysis was done. Time and frequency domain indices were computed. Simple and Choice Auditory and Visual reaction time (SART, CART, SVRT, CVRT) were measured. Results: BHR and DBP were significantly increased in traffic police. Time domain indices (Mean RR, SDNN, RMSSD, pNN50) were significantly reduced in traffic police. In frequency domain, Total Power was significantly reduced. LF-HF ratio was increased, though not significant. SVRT was significantly delayed in traffic police. CVRT, SART and CART were delayed in traffic police though not significant. Conclusion: Traffic police have decreased HRV with increased sympathetic and decreased vagal tone, and delayed reaction time.

Assessment of body fat mass index and basal metabolism to body fat ratio as markers of cardiovascular risk in obese Indian population

Background and Aim: Obesity is one among the prominent public health threats globally. Altered body composition and increased basal metabolism (BM) have been reported in obesity. However, the association of body composition and metabolic indices with cardiovascular (CV) risk in obese Indian population has not been studied. Therefore, the purpose of the present study was to determine the independent contribution of body composition and BM indices to CV risk in apparently healthy obese subjects. Methods: Basal CV and body composition parameters were recorded in 100 subjects divided into controls ( n = 48) and obese ( n = 52) groups. Association and independent contribution of body mass index (BMI), BM to body fat (BM/BF) ratio and BF mass index (BFMI) with rate pressure product (RPP), an established CV risk was performed by Pearson's correlation and multiple regression analysis, respectively. Results: Basal CV parameters were significantly increased in obese group compared to controls. Body composition parameters were also found to be significantly altered in obese group compared to controls. BMI, BM/BF, and BFMI had an independent contribution to RPP in the obese group, whereas no such association was observed in controls. Among these parameters, RPP had maximum association with BFMI (β =0.411, P ≤ 0.001) and BM/BF (β =0.373, P = 0.005) in obese group. Conclusion: Findings of the present study demonstrates increased RPP in obese subjects, predisposing them to future cardiac related morbidities. BFMI and BM/BF ratio appears to be better markers of CV risk in obese Indian population.

A prospective study on the relationship between blood pressure and blood group among adult male blood donors in a Tertiary care center

Background and Aim: The ABO blood type, an easily accessible factor in patient's genetic make-up has been associated with many diseases; perhaps the ABO antigens play a role by influencing renin levels. It may be speculated that since blood pressure (BP) is multifactorial, the ABO antigens may indirectly influence arterial pressure. Therefore, in the present study, we intend to assess the relationship between BP and blood group among the male blood donors (20-60 years) attending the blood bank in a tertiary care center. Methods: Basal cardiovascular parameters such as basal heart rate, systolic BP, diastolic BP (DBP) and rate pressure product (RPP) were recorded. ABO and Rh (D) blood groups were also determined for each subject. Tube test for ABO and Rh typing of red cells and serum typing was done on the donor blood samples. Results: The test group comprised of 767 subjects within the age-group of 20-60 years. All the values were expressed as mean ± standard deviation with the P Conclusion: There was a positive correlation between DBP and blood groups, but RPP was not found to be significant between the groups. Hence, we presume that further studies with a population-based screening of various blood groups might help in identifying and modifying the risk factors for hypertension.

Analysis of Poincare plot of heart rate variability in the assessment of autonomic dysfunction in patients with polycystic ovary syndrome

Background and Aim: Polycystic ovary syndrome (PCOS) due to its constant association with obesity poses a significant cardiovascular (CV) risk. Heart rate variability (HRV) has been a noninvasive marker of autonomic dysfunction and CV risk. This study was designed to assess the nonlinear dynamics of HRV using Poincare plot in patients with PCOS and elucidate its importance in predicting the CV risk. Methods: A total of 45 women with newly diagnosed PCOS and 45 controls were recruited for the study. Waist-hip ratio, body mass index (BMI), basal CV parameters such as basal heart rate (BHR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and rate pressure product (RPP) were recorded. HRV analysis was done using both linear (time domain and frequency domain) and nonlinear measures (Poincare plot). Results: The cases had increased basal heart rate, BMI, SBP, DBP, MAP, and RPP. In linear measures of HRV, the total power (TP), which depicts overall HRV was reduced, and the ratio of low-frequency to high-frequency (LF-HF) was significantly increased in cases. In nonlinear measures, the standard descriptors (SD1 and SD2) and area of the ellipse (S) were decreased, which signifies decreased HRV. There was a significant correlation of linear measures (TP, LF-HF ratio) and nonlinear measures (SD1, SD2, S) with elevated RPP. Both linear and nonlinear measures had independent contribution to elevated RPP, observed from regression analysis. Conclusion: Decreased HRV and autonomic dysfunctions in the form of increased sympathetic drive and decreased vagal activity were observed in PCOS patients that may herald CV risks. Poincare plot analysis can independently quantify the magnitude of autonomic dysfunction in PCOS.

Cardiovascular complications following chronic treatment with cocaine and testosterone in adolescent rats.

Concomitant use of anabolic androgenic steroids and cocaine has increased in the last years. However, the effects of chronic exposure to these substances during adolescence on cardiovascular function are unknown. Here, we investigated the effects of treatment for 10 consecutive days with testosterone and cocaine alone or in combination on basal cardiovascular parameters, baroreflex activity, hemodynamic responses to vasoactive agents, and cardiac morphology in adolescent rats. Administration of testosterone alone increased arterial pressure, reduced heart rate (HR), and exacerbated the tachycardiac baroreflex response. Cocaine-treated animals showed resting bradycardia without changes in arterial pressure and baroreflex activity. Combined treatment with testosterone and cocaine did not affect baseline arterial pressure and HR, but reduced baroreflex-mediated tachycardia. None of the treatments affected arterial pressure response to either vasoconstrictor or vasodilator agents. Also, heart to body ratio and left and right ventricular wall thickness were not modified by drug treatments. However, histological analysis of left ventricular sections of animals subjected to treatment with testosterone and cocaine alone and combined showed a greater spacing between cardiac muscle fibers, dilated blood vessels, and fibrosis. These data show important cardiovascular changes following treatment with testosterone in adolescent rats. However, the results suggest that exposure to cocaine alone or combined with testosterone during adolescence minimally affect cardiovascular function.

Association of sympathovagal imbalance with cardiovascular risks in patients with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is associated with cardiovascular risks like obesity, insulin resistance, dyslipidemia that can lead to sympathovagal imbalance (SVI). The study was designed to assess the cardiovascular risk in PCOS and link of metabolic derangements to SVI. Thirty-five newly diagnosed PCOS patients and 32 age-matched controls were recruited. Waist-hip ratio, body mass index (BMI), basal cardiovascular parameters such as basal heart rate (BHR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and rate pressure product (RPP) were recorded. Autonomic functions were assessed using short-term heart rate variability (HRV) analysis, heart rate and blood pressure response to standing (30:15 ratio), deep breathing (E:I ratio) and isometric handgrip (ΔDBPihg). Fasting plasma glucose, insulin, lipid profile and testosterone were assayed. Insulin resistance (HOMA-IR) and lipid risk factors were calculated. The cases had increased BHR, BMI, SBP, DBP, MAP and RPP. The ratio of low-frequency to high-frequency (LF–HF) of HRV, the marker of SVI was significantly increased in cases. 30:15 ratio and ΔDBPihg were increased and E:I ratio was decreased in the cases. HOMA-IR, lipid risk factors and testosterone were significantly elevated in cases. There was a significant correlation of LF–HF with BMI, BHR, RPP, insulin resistance and lipid risk factors. On regression analysis, insulin resistance and lipid risk factors had independent association with LF–HF. PCOS patients have SVI, decreased HRV and increased RPP and the potential cardiovascular risks. The insulin resistance and dyslipidemia contribute to SVI and cardiovascular risks in PCOS patients.

Assessment of heart rate variability indices in overweight and obese Indian population

Background and Aim: Due to the increased incidence of overweight and obesity, its associated co-morbidities have also been reported to be escalating. Resting tachycardia, increased rate pressure product (RPP) and decreased heart rate variability (HRV) contribute to cardiovascular (CV) risks. Therefore, in the present study HRV indices and CV risks in overweight and obese subjects have been assessed. Methods: Body mass index (BMI), waist circumference, waist-to-hip ratio, waist-to-height ratio (WHtR) and basal CV parameters were assessed in control ( N = 50), overweight ( N = 50) and obese ( N = 50) group subjects. Spectral analysis of HRV was performed in all these groups using Biopac system. Results: The basal CV parameters were significantly increased in overweight and obese subjects compared to controls. Low-frequency to high-frequency ratio (LF-HF ratio), marker of sympathovagal imbalance (SVI) was increased in overweight and obese subjects compared to controls. Total power (TP) and high frequency component expressed as normalized unit (Hfnu) which reflects the overall vagal drive to heart, was significantly decreased and low frequency component expressed as normalized unit (Lfnu) which reflects the sympathetic cardiac modulation, was significantly increased, in overweight and obese subjects compared to controls. These CV risks were predominately more in obese compared to overweight subjects. Conclusion: Increased resting heart rate, RPP and decreased HRV due to sympathetic activation and vagal withdrawal observed in overweight and obese subjects might contribute to the increased CV risk in these high risk populations.

Association of heart rate variability indices with inflammatory markers in non-diabetic obese dyslipidemic middle aged Saudi population

Background and Aim: It has been documented that obesity is associated with diabetes, hypertension and dyslipidemia that are known cardiovascular (CV) risks. However, there are few obese individuals, who do not develop diabetes early. In the present study, we have assessed the association of inflammatory markers in non-diabetic dyslipidemic obese subjects, as metabolic biomarkers have not been adequately studied in obesity without diabetes, especially in the assessment of CV risks. Methods: Twenty non-diabetic obese dyslipidemic subjects (study group) and 20 healthy non-obese subjects (control group) were included in this study. They were assessed for their body mass index (BMI) and heart rate variability (HRV) indices. Glucose, insulin, lipid profile and inflammatory markers were estimated from the fasting serum sample. Association of HRV with various parameters was determined by Pearson's correlation analysis. Results: The basal CV parameters, HRV, lipid profile, glucose, insulin and the inflammatory markers were significantly altered and correlated with ratio of low frequency to high frequency (LF: HF ratio), a marker of sympathovagal imbalance (SVI) in the study group when compared with the control group. Conclusion: SVI in the form of increased sympathetic and decreased parasymapathetic activity occurs in non-diabetic obese dyslipidemic subjects. Association of BMI, metabolic parameters and chronic low grade inflammation with LF: HF ratio may partly explain their augmented risks to future cardiac morbidities.

Partial Restoration of Cardiovascular Function by Embryonic Neural Stem Cell Grafts after Complete Spinal Cord Transection

High-level spinal cord injury can lead to cardiovascular dysfunction, including disordered hemodynamics at rest and autonomic dysreflexia during noxious stimulation. To restore supraspinal control of sympathetic preganglionic neurons (SPNs), we grafted embryonic brainstem-derived neural stem cells (BS-NSCs) or spinal cord-derived neural stem cells (SC-NSCs) expressing green fluorescent protein into the T4 complete transection site of adult rats. Animals with injury alone served as controls. Implanting of BS-NSCs but not SC-NSCs resulted in recovery of basal cardiovascular parameters, whereas both cell grafts alleviated autonomic dysreflexia. Subsequent spinal cord retransection above the graft abolished the recovery of basal hemodynamics and reflexic response. BS-NSC graft-derived catecholaminergic and serotonergic neurons showed remarkable long-distance axon growth and topographical innervation of caudal SPNs. Anterograde tracing indicated growth of medullar axons into stem cell grafts and formation of synapses. Thus, grafted embryonic brainstem-derived neurons can act as functional relays to restore supraspinal regulation of denervated SPNs, thereby contributing to cardiovascular functional improvement.

Effect of the Single or Combined Administration of Cocaine and Testosterone on Cardiovascular Function and Baroreflex Activity in Unanesthetized Rats

Abuse of cocaine and androgenic-anabolic steroids has become a serious public health problem. Despite reports of an increase in the incidence of simultaneous illicit use of these substances, potential toxic interactions between cocaine and androgenic-anabolic steroids in the cardiovascular system are unknown. In the present study, we investigated the effect of single or combined administration of testosterone and cocaine for 1 or 10 consecutive days on basal cardiovascular parameters, baroreflex activity, and hemodynamic responses to vasoactive agents in unanesthetized rats. Ten-day combined administration of testosterone and cocaine increased baseline arterial pressure. Changes in arterial pressure were associated with altered baroreflex activity and impairment of both hypotensive response to intravenous sodium nitroprusside and pressor effect of intravenous phenylephrine. Chronic single administration of either testosterone or cocaine did not affect baseline arterial pressure. However, testosterone-treated animals presented rest bradycardia, cardiac hypertrophy, alterations in baroreflex activity, and enhanced response to sodium nitroprusside. Repeated administration of cocaine affected baroreflex activity and impaired vascular responsiveness to both sodium nitroprusside and phenylephrine. One-day single or combined administration of the drugs did not affect any parameter investigated. In conclusion, the present results suggest a potential interaction between toxic effects of cocaine and testosterone on the cardiovascular activity. Changes in baseline arterial pressure after combined administration of these 2 drugs may result from alterations in baroreflex activity and impairment of vascular responsiveness to vasoactive agents.

Absence of gp130 in dopamine β-hydroxylase-expressing neurons leads to autonomic imbalance and increased reperfusion arrhythmias

Inflammatory cytokines that act through glycoprotein (gp)130 are elevated in the heart after myocardial infarction and in heart failure. These cytokines are potent regulators of neurotransmitter and neuropeptide production in sympathetic neurons but are also important for the survival of cardiac myocytes after damage to the heart. To examine the effect of gp130 cytokines on cardiac nerves, we used gp130(DBH-Cre/lox) mice, which have a selective deletion of the gp130 cytokine receptor in neurons expressing dopamine beta-hydroxylase (DBH). Basal sympathetic parameters, including norepinephrine (NE) content, tyrosine hydroxylase expression, NE transporter expression, and sympathetic innervation density, appeared normal in gp130(DBH-Cre/lox) compared with wild-type mice. Likewise, basal cardiovascular parameters measured under isoflurane anesthesia were similar in both genotypes, including mean arterial pressure, left ventricular peak systolic pressure, dP/dt(max), and dP/dt(min). However, pharmacological interventions revealed an autonomic imbalance in gp130(DBH-Cre/lox) mice that was correlated with an increased incidence of premature ventricular complexes after reperfusion. Stimulation of NE release with tyramine and infusion of the beta-agonist dobutamine revealed blunted adrenergic transmission that correlated with decreased beta-receptor expression in gp130(DBH-Cre/lox) hearts. Due to the developmental expression of the DBH-Cre transgene in parasympathetic ganglia, gp130 was eliminated. Cholinergic transmission was impaired in gp130(DBH-Cre/lox) hearts due to decreased parasympathetic drive, but tyrosine hydroxylase immunohistochemistry in the brain stem revealed that catecholaminergic nuclei appeared grossly normal. Thus, the apparently normal basal parameters in gp130(DBH-Cre/lox) mice mask an autonomic imbalance that includes alterations in sympathetic and parasympathetic transmission.

Prenatal stress alters cardiovascular responses in adult rats.

Environmental factors in early life are clearly established risk factors for cardiovascular disease in later life. Most studies have focused on nutritional programming and analysed basal cardiovascular parameters rather than responses. In the present study we have investigated whether prenatal stress has long-term effects on cardiovascular responses in adult offspring. Female pregnant Sprague-Dawley rats were subjected to stress three times daily from day 15 to day 21 of gestation. Litters from stressed and control females were cross-fostered at birth to control for mothering effects. When the offspring were 6 months old, blood pressure was measured in the conscious rats through implanted catheters at rest, during restraint stress and during recovery. Basal haemodynamic parameters were similar in the different groups but the pattern of cardiovascular responses during stress and recovery differed markedly between prenatally stressed (PS) and control animals. PS rats had higher and longer-lasting systolic arterial pressure elevations to restraint stress than control animals. They also showed elevated systolic and diastolic blood pressure values during the recovery phase. PS rats demonstrated a greater increase in blood pressure variability compared with control animals during exposure to restraint stress, and showed more prolonged heart rate responses to acute stress and delayed recovery than controls. There was no effect of prenatal stress on baroreflex regulation of heart rate. PS females showed a greater increase in systolic arterial pressure and blood pressure variability and delayed heart rate recovery following return to the home cage then did PS males. These findings demonstrate for the first time that prenatal stress can induce long-term, sex-related changes in the sensitivity of the cardiovascular system to subsequent stress.