Neuroendocrine reflex

Diazoxide appears to have a direct antinatriuretic action. This direct action, coupled with the neuroendocrine reflexes that are activated by a decrease in pe-... 

Another way in which hormonal secretion is regulated involves a neuroendocrine reflex, which differs from a neural reflex in that the efferent neuron is replaced by a... 

Complex feedback regulation of hormone secretion. Hormones of level III endocrine ti,s,sues are regulated by a complex system having both a neuroendocrine reflex component and a simple negative feedback component. Invariably, the former involves the extrahypothalamic central nervous system (sensory neurons), the hypothalamus (endocrine cell 1), and the anterior pituitary (endocrine cell 2), while the latter involves the anterior pituitary (endocrine cell 2) and a level III endocrine tissue (endocrine cell 3). Hormone 3 exerts negative feedback on endocrine cell 2 and hence on its own secretion. Hormone 3 may also feed back to endocrine cell I and to higher centers, although such ca.ses of feedback may be positive ones. 

The posterior lobe of the pituitary gland releases antidiuretic hormone (ADH) in response to serum osmolality. High serum osmolality causes the release of ADH, which directs the kidneys to conserve water to restore fluid concentration balance. Low serum osmolality or bigh blood pressure can result in a neuroendocrine reflex... 

Although vasodilators would appear to be ideal drugs for the treatment of hypertension, their effectiveness, particularly when they are used chronically, is severely limited by neuroendocrine and autonomic reflexes that tend to counteract the fall in blood pressure. How these reflexes compromise the fall in blood pressure produced by the vasodilators is shown in Fig. 20.1. The diagram does not show all of the possible interrelationships but rather is meant to draw attention to the most prominent reflex changes. These reflexes include an augmentation of sympathetic nervous activity that leads... 

Lim followed up his observation that when a dog eats a bone, a meal of bulk only, the dog s stomach secretes acid by returning to his earlier study of the effect of distention on gastric secretion. With H-C Chang he demonstrated that distention of a pouch of the pyloric part of the stomach resulted in secretion by the dog s Hei-denhain pouch. Lim considered the possibility that the effect was mediated by a reflex through sympathetic nerves or that in some way distention of the pyloric pouch releases the Heidenhain pouch from inhibition. By this time (1931) Lim was aware of the work of Otto Loewi and of Walter B. Cannon in demonstrating chemical mediation of nerve impulses, and he concluded that mechanical irritation of the pylorus involves the neuroendocrine mechanism of liberation of a hormone. ... 

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