Affiliation:
1. Department of Biology, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5.
Abstract
The goal of the present investigation was to assess the relative involvement of nicotinic and muscarinic cholinergic receptors in the neuronal control of catecholamine secretion from the chromaffin tissue of rainbow trout (Oncorhynchus mykiss). This was accomplished by first developing and validating a nerve-stimulating technique able specifically to activate the nerve fibres innervating the chromaffin cells in order to elicit secretion of catecholamines. Using an in situ saline-perfused posterior cardinal vein preparation, it was demonstrated that whole-body field stimulation caused specific voltage-dependent neuronal stimulation of adrenaline and noradrenaline secretion. The contribution of non-specific depolarization was negligible. Several experimental results confirmed the specificity of the field stimulation technique. First, pre-treatment with neostigmine (an anticholinesterase) prolonged and more than doubled the amount of adrenaline secreted in response to electrical stimulation. Second, pre-treatment with the nicotinic receptor antagonist hexamethonium inhibited the electrically evoked secretion of adrenaline and noradrenaline. Third, perfusion with Na+-free saline or removal of the spinal cord abolished secretion of both catecholamines in response to the electrical stimulus. By using the field stimulation technique, this study is the first to demonstrate conclusively a role for muscarinic receptors in catecholamine secretion from trout chromaffin cells. Specifically, muscarinic cholinergic stimulation enhances nicotinic-evoked secretion of catecholamines and, under intense stimulation, may directly cause secretion. The results of the present study suggest the presence of muscarinic receptors on rainbow trout chromaffin cells with a functional role in the cholinergic control of catecholamine secretion.
Publisher
The Company of Biologists
Subject
Insect Science,Molecular Biology,Animal Science and Zoology,Aquatic Science,Physiology,Ecology, Evolution, Behavior and Systematics
Reference37 articles.
1. Electrostimulation of catecholamine release in the eel: modulation by antagonists and autocrine agonists;Abele;Gen. Comp. Endocr,1998
2. The chromaffin cells of urodele amphibians;Accordi;J. Anat,1991
3. Cholinergic control of catecholamine release in the eel;Al-Kharrat;Gen. Comp. Endocr,1997
4. Control of catecholamine and serotonin release from chromaffin tissue of the Antlantic hagfish;Bernier;J. Exp. Biol,1996
5. Angiotensins stimulate catecholamine release from the chromaffin tissue of the rainbow trout;Bernier;Am. J. Physiol,1997
Cited by
19 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献