Effects of taurine on stress-evoked hemodynamic and plasma catecholamine changes in spontaneously hypertensive rats.

Abstract

SUMMARY Cardiovascular hemodynamics (microspheres) and plasma norepinephrine and epinephrine levels at rest and during short-term shaker stress were investigated in conscious spontaneously hypertensive rats and Wistar-Kyoto rats, with or without oral taurine (1.5%) treatment for 8 weeks. Taurine effects were evaluated by comparing data on the taurine-treated and untreated rats. Taurine affected neither the resting hemodynamics nor the resting plasma catecholamine levels in spontaneously hypertensive and Wistar-Kyoto rats. Taurine slightly but significantly reduced the left ventricular/body weight ratio in the spontaneously hypertensive rats (p < 0.05) and caused an insignificant 10 mm Hg decrease in the resting mean arterial pressure. Spontaneously hypertensive and Wistar-Kyoto rats responded in a qualitatively similar manner to stress, as evidenced by resistance-dominated increases in mean arterial pressure and increases in heart rate, with a blood flow redistribution from splanchnic, cutaneous, and testicular to skeletal muscle and cerebral circulations and by increases in plasma norepinephrine and epinephrine levels. These changes were more marked in the spontaneously hypertensive rats. Taurine significantly reduced the stress values of mean arterial pressure (untreated, 189 ± 4 (SE) mm Hg; treated, 166 ± 4 mm Hg in the spontaneously hypertensive rats; p < 0.05), while it significantly reduced stress values of heart rate in spontaneously hypertensive and Wistar-Kyoto rats (p < 0.05). Taurine also blunted the stress values of splanchnic, testicular, and cutaneous vascular resistance in the spontaneously hypertensive rats. There were no or only slight regional effects in the Wistar-Kyoto rats. Taurine substantially decreased plasma levels of norepinephrine (untreated, 615 ± 76 pg/ml; treated, 383 ± 49 pg/ml) and epinephrine (untreated, 892 ± 187 pg/ml; treated, 232 ± 59 pg/ml) during stress in the spontaneously hypertensive rats. These results indicate that chronic taurine treatment attenuates short-term shaker stress-induced hemodynamic and plasma catecholamine changes in spontaneously hypertensive rats. (Hypertension 7: 913-922, 1985) KEY WORDS • shaker stress • systemic and regional hemodynamics sympathoadrenomedullary activity P ATIENTS with essential hypertension, and even their normotensive adolescent offspring, often show hyperresponsiveness to physical and psychological stress. '• 2 Likewise, adult and young spontaneously hypertensive rats (SHR), the most ex-

Impact of taurine supplementation on blood pressure in gestational protein-restricted offspring: Effect on the medial solitary tract nucleus cell numbers, angiotensin receptors, and renal sodium handling

“…44,45 Taurine may also reduce blood pressure through attenuation of peripheral AngII activity, enhancement of the kinin-kallikrein system in the kidney, 46,47 or decreasing levels of epinephrine and norepinephrine. Additionally, as observed in the current study, taurine supplementation effectively normalizes high blood pressure in the most common animal models of hypertension, including: spontaneously hypertensive rats (SHR), 48 deoxycorticosterone acetate (DOCA)-salt rats, 49 and Dahl-S rats. 50 …”

Cardiovascular responses to acute stress in young-to-old spontaneously hypertensive rats.

“…Tip-tapered PE-50 catheters (Clay Adams, Parsippany, NJ, USA) were introduced into the femoral artery and vein, respectively, and into the left ventricle through the right carotid artery. 22 - 30 All catheters were brought out through subcutaneous tunnels in the dorsal cervical region. The wounds were treated with 1% lidocaine and sutured.…”

“…2231 This shaker stress evoked responses that combined emotional arousal with consequent behavioral and, hence, skeletal muscle excitation. Since circulatory variables were most stable between 2 and 3 minutes, 22 the second hemodynamic measurement was made during this period, using a different set of radioactive microspheres, as already described.…”

“…Cardiac and peripheral hemodynamic variables were calculated using the reference and tissue sample radioactivity, based on standard equations. 22 - 30 Cardiac output and regional blood flow were reported as ml/min/100 g of body or tissue weight; cardiac output was referred to as cardiac index. Total peripheral and regional vascular resistances were expressed as mm Hg/ml/min/100 g of body or tissue weight.…”

Forearm blood flow responses of offspring of hypertensives to an extended stress task.

“…It is possible that differences in affective reactivity between individuals with and without a family history of hypertension are elicited only by fairly intense stressors (e.g., shock avoidance). It is tempting to point to evidence of high emotionality in spontaneously hypertensive rats 31 and suggest that genetic factors might contribute to a general hyperresponsiveness to environmental stimulation mediated by the limbic and hypothalamic areas that can be observed in physiological, behavioral, and affective parameters. In a series of studies, Baer and coworkers 3233 found that families with hypertensive fathers tend to exhibit more negative nonverbal behaviors (e.g., gaze aversion) than families without hypertensive parents, and that there may be some relation between the frequency of negative nonverbal behaviors in parents and the blood pressure levels of children.…”