George E. Farrar

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Serotonin (5-HT) is generally considered to serve a facilitatory role in the regulation of adrenocortical secretion. Numerous studies have shown that administration of 5-HT1A receptor agonists increases plasma corticosterone (CS) concentrations in rats; however, the mechanism has not been established. Rats were prepared with a cannula implanted above the(More)
Cocaine (COC) has been described as exerting potent stimulatory effects on the hypothalamo-pituitary-adrenocortical (HPA) axis. In the present study, we investigated the acute and chronic effects of intracerebroventricular and intrahypothalamic injections of COC in rats. Twenty minutes following intracerebroventricular injection of COC (1-100 micrograms),(More)
The present studies were designed to determine the effects of 5-HT1A receptor agonists and 5-HT2A/2C and 5-HT3 antagonists on adrenocortical responses to a variety of stress paradigms in conscious male rats. The following stressors were examined: acoustic stress (105 dB for 2 min); foot shock (0.2 mA, five shocks over 5 min); conditioned fear (animals(More)
This study was designed to determine the effects of portal hypertension on intestinal myoelectrical activity and propulsion. In a single surgery, adult rats were implanted with a serosal electrode at each quarter of the small intestine, and portal hypertension was produced by calibrated constriction of the portal vein. To determine intestinal transit,(More)
In our earlier studies we have demonstrated that recombinant human interferon-alpha 2A (rHu-IFN-alpha 2A) inhibits hypothalamo-pituitary-adrenocortical (HPA) secretion following both peripheral and central administration. Furthermore, this effect is antagonized by mu-opioid receptor antagonists, suggesting transduction by this subtype of opioid receptors.(More)
Double-labeling immunohistochemical studies were performed to discern the morphological relationships between corticotropin-releasing factor-immunoreactive (CRF-ir) perikarya and afferent innervation in the hypothalamic paraventricular nucleus (PVN) of the rat. Attention was focussed on the local innervation by serotonin (5-hydroxytryptamine, 5-HT),(More)
Heart rate, mean arterial pressure, and vascular conductance response to intravenous nitroprusside were compared in conscious, unrestrained portal vein-stenosed and sham-operated rats chronically instrumented for pulsed Doppler flowmetry. Ten to twelve days after portal vein stenosis, portal venous pressures were elevated and resting heart rates were(More)