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H J Lynch

Publications and source records attributed to H J Lynch.

50 records · Page 3Linked to original sources
PubMed1973

Control of pineal indole biosynthesis by changes in sympathetic tone caused by factors other than environmental lighting.

The melatonin (5-methoxy-N-acetylserotonin) content and N-acetyltransferase activity of rat pineal increase rapidly in response to physical immobilization or insulin-induced hypoglycemia. Carbohydrate consumption, which causes insulin release without hypoglycemia, does not elicit these pineal responses. Prior treatment with propranolol, a beta-adrenergic blocking agent, inhibits the N-acetyltransferase responses to hypoglycemia and immobilization, indicating that these changes result from stimulation of pineal beta-receptors by a catecholamine, presumably norepinephrine released from pineal sympathetic nerve terminals. Prior destruction of those terminals with 6-hydroxydopamine does not block, but actually potentiates, the increase in melatonin content and N-acetyltransferase activity after induced hypoglycemia or immobilization. This finding probably reflects an action of circulating catecholamines, secreted from the adrenal medullae or surviving sympathetic nerve terminals, on supersensitive pineal cells. These observations indicate that factors other than changes in environmental lighting, which modify sympathetic nervous tone, can also influence pineal function.

Acetyltransferases↗
PubMed1970

Pineal function and oviposition in Japanese quail: superior cervical ganglionectomy and photoperiod.

Bilateral ablation of the superior cervical ganglia appears to deprive the pineal body of sympathetic innervation. Although this procedure presumably interrupts the neural circuit for transmission of optic information to the pineal, oviposition rates of ganglionectomized females exposed to stimulatory (15-hour) or to nonstimulatory (4-hour) daily photoperiods do not differ from those of the controls.

Animals↗
PubMed1968

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Community Health Services↗