[Role of M-type receptor in internal calcium release and quantal secretion in rat adrenal chromaffin cells].
In rat single adrenal chromaffin cells, the effects of methacholine (MCh) on [Ca2+]i and catecholamine secretion were studied with fura-2 fluorescence and carbon fiber electrodes. In the presence of 2 mmol/L Ca2+ in the bath, locally applying 1 mmol/L MCh, either containing or not containing Ca2+, evoked both [Ca2+]i and secretion signals. In the absence of Ca2+ in the bath, MCh could still evoke [Ca2+]i and secretion. These results suggest that MCh causes release of Ca2+ from Ca2+ stores, which is sufficient to yield the evoked secretion. The Ca2+ store can be depleted by single MCh puff in the absence of Ca2+ in the bath.
Xu
J H
JH
Institute of Biophysical Biochem, Huazhong University of Science and Technology, Wuhan 430074.
Zeng
X H
XH
He
L M
LM
Qu
A L
AL
Zhou
Z
Z
D000313:Adrenal Medulla / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002395:Catecholamines / Q000378:metabolism; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000378:metabolism*; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000502:physiology*
D002395:Catecholamines; D011976:Receptors, Muscarinic; D016210:Methacholine Chloride; D002118:Calcium