Monica J. McCann

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Systemic administration of cholecystokinin octapeptide (CCK-8) prompts an abrupt increase in circulating levels of oxytocin (OXY) but not vasopressin (VP) in rats. The present study determined whether CCK-8 selectively stimulated OXY-secreting neurons in the hypothalamic supraoptic nucleus of pentobarbital-anesthetized male rats. Antidromically identified(More)
Administration of cholecystokinin (CCK) to rats caused a dose-dependent increase in plasma levels of the neurohypophyseal hormone oxytocin (OT). The OT secretion was comparable to that found in response to nausea-producing chemical agents that cause learned taste aversions. The effect of CCK on OT secretion was blunted after gastric vagotomy, as was the(More)
1. Dorsal medullary injections of oxytocin (OT) influence gastric motor and secretory function via a vagally mediated mechanism. Thus, it was hypothesized that OT altered the firing rate of brain stem vagal neurones that were specifically related to gastric function. 2. To study this, glass microelectrode/injection pipette arrays were used to record the(More)
Systemic injection of the nauseogenic agent LiCl is known to increase neurohypophyseal secretion of oxytocin (OT) in rats. The present results indicated that the induced OT secretion was related exponentially to the inhibition of food intake. A similar relation between OT secretion and food intake also was observed after systemic injection of the peptide(More)
The local circuit neurons in the solitary nucleus that form part of a gastro-gastric vago-vagal reflex were examined using a biocytin/avidin-peroxidase histochemical tracing method in the male Long-Evans rat. Iontophoretic deposits of very small amounts of biocytin were made into the ventral commissural nucleus of the solitary tract (vcNTS) where the(More)
1. Activation of gastric sensory afferents alters gastric motor and secretory function via the gastric vago-vagal reflex. In this report, we investigated in the rat the impact of gastric mechanoreceptor activation on the brain stem components of the reflex, which are located in the dorsal vagal complex (DVC), i.e. the nucleus of the solitary tract (NTS) and(More)
Systemic injection of the peptide hormone cholecystokinin (CCK) is known to inhibit food intake and gastric emptying, and to stimulate neurohypophyseal secretion of oxytocin (OT) in rats. Previous studies also have shown that surgical destruction of afferent fibers in the gastric vagus eliminates the inhibitory effects of CCK on food intake. The present(More)
Previous reports have demonstrated that intraventricular administration of thyrotropin-releasing hormone (TRH) markedly elevates parasympathetic efferent activity. The following study determined if this response could be attributed to an effect of TRH on the neurons in the dorsal motor nucleus of the vagus (DMN) and/or the nucleus tractus solitarius (NTS),(More)
Because the nucleus raphe obscurus (nRO) maintains a direct connection with the dorsal vagal complex in the medulla, this nucleus has the potential to influence vagal control of gastric function. Both electrical- and glutamate-induced activation of the nRO were found to enhance gastric motility and tone in the rat. The gastric responses to nRO stimulation(More)
Previous work has established that the increased food intake of rats in response to insulin-induced hypoglycemia can be inhibited by the intravenous infusion of fructose, a sugar that cannot cross the blood-brain barrier and nourish cerebral chemoreceptors, and that this effect of fructose is abolished by hepatic vagotomy. The present series of experiments(More)