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Non-cholinergic nervous control of catecholamine secretion from perfused bovine adrenal glands
1. Field stimulation of adrenal nerves was used to study nervous control of adrenal catecholamine secretion in isolated, retrogradely perfused, bovine adrenal glands. 2. Secretion of both adrenaline and noradrenaline was maximal at 10 Hz. Secretion at 2 Hz was < 10% of maximum. Stimulating with t...
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Published in: | The Journal of physiology 1993-06, Vol.465 (1), p.489-500 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that cite this one |
Online Access: | Get full text |
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Summary: | 1. Field stimulation of adrenal nerves was used to study nervous control of adrenal catecholamine secretion in isolated, retrogradely
perfused, bovine adrenal glands. 2. Secretion of both adrenaline and noradrenaline was maximal at 10 Hz. Secretion at 2 Hz
was < 10% of maximum. Stimulating with trains of pulses at ten times the average frequency for 1 s out of every 10 s gave
2-fold greater secretion at 2 Hz average frequency, similar release at 5 Hz, and only half the secretion at 10 Hz, compared
to continuous stimulation at the average frequency. 3. At 10 Hz, adrenaline and noradrenaline secretion was virtually abolished
by tetrodotoxin (1 microM), but was only reduced by 75% by prolonged perfusion with a combination of mecamylamine (5 microM)
and atropine (1 microM). Mecamylamine and atropine completely abolished the secretory response to 2 Hz stimulation. Tetrodotoxin
had no significant effect on secretion induced by perfusing glands with nicotine (5 microM), while mecamylamine abolished
this response. Mecamylamine and atropine had no effect on secretion induced by K+ depolarization. 4. The secretion of adrenaline
and noradrenaline induced by 10 Hz stimulation was not inhibited by naloxone at either 1 or 30 microM. 5. The results suggest
that bovine adrenal chromaffin cells, like those in the rat, receive a significant non-cholinergic secretomotor innervation.
In contrast to the rat, however, the non-cholinergic component in the bovine adrenal is negligible at low-frequency nerve
stimulation and substantial at higher frequencies, and is not antagonized by naloxone. The identity of the non-cholinergic
transmitter remains to be determined. |
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ISSN: | 0022-3751 1469-7793 |
DOI: | 10.1113/jphysiol.1993.sp019689 |