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Biomedical subjects

O A Smith

Publications and source records attributed to O A Smith.

At least 37 records · Page 2Linked to original sources
PubMed1979

Renal and hindlimb vascular control during acute emotion in the baboon.

Blood pressure, heart rate, oxygen consumption, and blood flow to the renal and hind-limb vasculatures were measured in healthy, unanesthetized baboons (Papio cynocephalus) in a controlled environment. Appropriate behavioral techniques were applied to allow the reproducible elicitation of a conditional emotional response (CER). Section of renal nerves and autonomic pharmacologic interventions were used to determine the mechanisms for the cardiovascular responses accompanying the CER. The resistance changes in the renal and hind-limb vascular beds were generated by rapid, neurally mediated vasoconstriction of the renal vasculature and by a slower acting, circulating vasoactive agent, most probably epinephrine, which causes a delayed second constriction in the renal bed and a net dilation in the hind limbs.

Animals↗
PubMed1976

Sudden death in infant primates from induced laryngeal occlusion.

Thirteen infant and juvenile monkeys and baboons were studied in procedures designed to assess the functional characteristics of the upper airway, with special attention to the consequences of laryngeal nerve stimulation. In young animals, stimulation of the recurrent laryngeal nerve produced closure of the airway in sufficient degree and duration to cause death. Older juvenile monkeys were resistant to fatal laryngospasm induced by nerve stimulation. A variety of patterns of general autonomic response accompanied the airway changes. These results are consistent with (1) a laryngospasm hypothesis to account for certain terminal events in sudden infant death syndrome, and (2) prior observations of age-related general autonomic stability.

Age Factors↗
PubMed1976

Elevation of plasma renin activity during avoidance performance in baboons.

The effect of a 3-h Sidman avoidance operant conditioning schedule (liver pressing to avoid an electric shock) on plasma renin activity and renin substrate concentration was examined in baboons (Papio cynocephalus). Plasma samples were drawn over a 24-h period on both the control and test days, and the avoidance session was presented on the morning of the test day. Plasma renin activity was significantly higher on the test day than at the corresponding hours of the control day at 1, 2, and 3 h after onset of the avoidance test and 30 min after its termination (P = .032). The magnitude of the increase in plasma renin activity was not correlated with either the rate of lever pressing or the number of shocks received. Renin substrate concentration was not changed during or after the avoidance session. These data demostrate that plasma renin activity can be increased by a psychological stimulus.

Angiotensin II↗
PubMed1975

Prefrontal control of conditioned suppression and associated cardiovascular variables in the monkey (Macaca mulatta).

Rhesus monkeys were trained in a discriminated conditioned emotional responses paradigm. The discriminated conditioned response (CR) complex consisted of bar-press suppression, increased terminal aortic blood flow, and increased arterial pressure. Bar-press suppression and blood flow responses were temporarily eliminated by single-stage bilateral prefrontal lobectomy but not by extensive posterior cortical ablation, 2-stage prefrontal lobe removal, or 3-stage prefrontal cortical surface ablation. The blood pressure CR was attenuated by almost every surgical operation. The changes in heart rate paralleled changes in general activity. These data indicate that the prefrontal lobes influence the conditioned suppression of ongoing rewarded behavior and the vascular responses accompanying the suppression. The time course for recovery of the somatic CR after lobectomy differed from those of the cardiovascular CRs.

Animals↗
PubMed1968

Differential conditional emotional and cardiovascular responses--a training technique for monkeys.

A training technique has been developed which combines classical differential conditioning and conditional emotional response (CER) procedures. After monkeys were trained to lever-press on a variable-interval schedule, two stimulus lights were presented. One light (CS) was always followed, upon termination, by electrical shock; the other light (DS) was never followed by shock. The response to the CS was a decreased rate of lever-pressing and increased heart rate and blood-flow velocity. None of these responses occurred to the DS. This technique eliminates the possibility of pseudoconditioning and provides measurement of both somatic and autonomic responses in a CER situation.

Animals↗