ISSN:
1432-1912
Keywords:
Adrenal Medulla
;
Non-Nicotinic Agents
;
Pilocarpine
;
Muscarinic Transmission
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Successive intravenous injections of nicotine cause a biphasic block of the adrenal medulla of the cat. During the early phase the adrenal glands fail to respond to any stimulant; however, during the late, non-depolarizing phase the glands respond to non-nicotinic agents (5-hydroxytryptamine, bradykinin and pilocarpine) and to potassium chloride at a time when there is a pronounced and insurmountable antagonism to nicotinic agents. During this late phase of the block the effects of most of these agents are enhanced, although the sensitivity to noradrenaline is not. The enhancement is abolished by hexamethonium, which lacks any effect on the sensitivity to noradrenaline. The results obtained with the muscarinic agent, pilocarpine, support the earlier postulate that transmission of impulses from the splanchnic nerve, as observed during the late phase of the block by nicotine, is mediated by muscarinic mechanisms sensitized by nicotine.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00508907
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