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The effect of continuous stimulation of splanchnic nerves at 1, 3, and 10 Hz on the secretion of catecholamines from the isolated rat adrenal gland was examined. Secretion evoked at 10 Hz declined over 60% in 1 h, and by the end of 4 h the secretion was only 10% of the initial value. The secretion evoked at 3 Hz was unchanged in the first hour, but showed a(More)
The results of the present experiments demonstrate that embryonic sympathetic neurons initially selected in culture by nerve growth factor could be subsequently supported by raising potassium concentration of the medium to 35 mM. Alternatively, neurons initially selected by 35 mM potassium could be supported in a normal culture medium but supplemented with(More)
Tryptic digestion of tyrosine hydroxylase (TH) isolated from rat adrenal glands labeled with 32Pi produced five phosphopeptides. Based on the correspondence of these phosphopeptides with those identified in TH from rat pheochromocytoma cells, four phosphorylation sites (Ser8, Ser19, Ser31, and Ser40) were inferred. Field stimulation of the splanchnic nerves(More)
The functional integrity of adrenal chromaffin storage vesicles was studied in the perfused rat adrenal gland subjected to intense exocytosis. Continuous perfusion with 55 mM K+-Krebs solution produced a large and uninterrupted secretion of catecholamines. Total amounts secreted within 45 min were 4.66 micrograms and represented almost 30% of the total(More)
The aim of the present study was (1) to evaluate the functional contribution of nicotinic and muscarinic receptors of the rat adrenal medullary cells in the secretion of catecholamines evoked by exogenous and endogenous acetylcholine, (2) to know whether the ratio of epinephrine to norepinephrine in the perfusate of the adrenal gland stimulated with various(More)
1. A method of studying the secretion of catecholamines (CA) in the isolated perfused rat adrenal gland by transmural stimulation or by application of acetylcholine (ACh) has been described. 2. Secretion of CA was practically linear in response to ACh administration, starting from 4.42 microM to 1.32 mM. Transmural stimulation enhanced secretion from a(More)
We used cultured rat chromaffin cells to test the hypothesis that Ca2+ entry but not release from internal stores is utilized for exocytosis. Two protocols were used to identify internal versus external Ca2+ sources: (a) Ca2+ surrounding single cells was transiently displaced by applying agonist with or without Ca2+ from an ejection pipette. (b)(More)
Pituitary adenylate cyclase-activating polypeptide (PACAP) is the most potent non-cholinergic neurotransmitter to stimulate catecholamine secretion from rat chromaffin cells; however, the mechanism of action is not clear. We used amperometric detection of exocytosis and indo-1 monitoring of [Ca2+]i to identify PACAP actions in cultured chromaffin cells.(More)
1. Effects of nicotinic (mecamylamine) and muscarinic (atropine) receptor antagonists were investigated on the secretion of catecholamines evoked by stimulation of splanchnic nerve terminals and acetylcholine in the isolated perfused adrenal gland of the rat to determine whether non-cholinergic substances released from nerve terminals participate in the(More)
Our past work on nucleoside toxicity in sympathetic neurons has clearly revealed that adenosine and 2'-deoxyadenosine (dAdo) have different mechanisms of action in inducing apoptotic death. For example, adenosine is toxic to neurons only during early phase of growth whereas dAdo kills even mature neurons. In this study, we hypothesize that dAdo-induced(More)