The influence of arterial baroreceptors in man on the variability of blood pressure and plasma catecholamines in man

Basal and reactive plasma catecholamine levels under stress and anesthesia in rabbits

The present study was undertaken to determine if electrical stimulation of the hypothalamic defense area (HDA) and baroreflex activation elicited by head up body tilt produced changes in plasma catecholamine (CA) levels in anesthetized rabbits. We also compared the effects of two anesthetics, isoflurane and sodium pentobarbital, upon basal and reactive CA levels, and upon autonomic reactivity. HDA stimulation was found to produce significant increases in plasma norepinephrine (NE) levels but not epinephrine (E) levels. Passive tilt was found to produce statistically significant increases in NE levels for both anesthetics used and a significant increase in E levels for animals anesthetized with isoflurane. Basal and reactive measurements provided evidence that pentobarbital has a more suppressive effect upon the autonomic nervous system than isoflurane: (a) Basal NE levels were significantly lower in pentobarbital anesthetized animals than in isoflurane-anesthetized animals; and (b) Baroreceptor sensitivity to a passive tilt stressor was significantly higher for animals anesthetized with isoflurane than for animals anesthetized with pentobarbital.

Behavioral assessment of anxiety in older adults. Some comments

The behavioral assessment of anxiety in older adults is reviewed in this article. Despite the high rate of anxiety symptoms uncovered during the course of large-scale epidemiological studies, the comprehensive evaluation of anxiety in this age group (55 and over) is not highly sophisticated at this juncture. In this review, diagnostic issues, psychometric evaluation, motoric assessment, and psychophysiological assessment are considered. Throughout the articles, gaps in the extant research are identified, and a research agenda for the future is developed.

Age differences in the consistency of cardiovascular response patterns in healthy women

To determine if response consistency is higher in older women, twenty young adult (mean = 20 years) and twenty-two elderly (mean = 82 years) women participated in a 20-min stress protocol including serial subtraction, anxiety and anger imagery tasks. All subjects were healthy and free of diagnosed cardiovascular disease. Heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) responses to the tasks were assessed. To allow comparisons of the effects of stress on different cardiovascular parameters, all baseline-stress change scores were converted to z-scores. Forty-two 3(parameter)X3(stressor) matrices of z-scores, one for each subject, were created. Intraclass correlations computed using these matrices revealed greater consistency of response hierarchies (e.g., DBP greater than SBP greater than HR) among elderly subjects. Possible mechanisms for this effect are discussed.

Therapeutic effect of exercise on hypertension

Arterial blood pressure, total peripheral resistance (TPR), plasma catecholamine and other hormone concentrations were measured or estimated during, and 4 h following, a 20-min exercise test on the bicycle ergometer in 10 women with marginal (borderline) hypertension. Each woman served as her own control by repeating the whole procedure, except for the exercise test, on another day. Median and 80% range was used: M (0.8 R). Compared with the control, the exercise reduced the driving blood pressure from 103 (94-110) to 95 (80-100) mm Hg and the TPR from 1.13 (0.96-1.40) to 0.91 (0.79-1.11) PRUs - both reductions being statistically significant with two-sided P less than 0.05 for at least 4 h. - The reduced nervous and humoral sympathetic activity following aerobic exercise seems capable of explaining the low TPR, and the continuous rise in the muscular vasodilatator dopamine may be of importance.