Role of membrane depolarization in transsynaptic induction of tyrosine hydroxylase in organ cultures of sympathetic ganglia.
In contrast to nicotinic cholinomimetics which generate action potentials in postganglionic adrenergic neurons, general non-specific depolarizing agents such as veratridine and batrachotoxin (which also generate action potentials) do not initiate tyrosine hydroxylase (TH) induction. Moreover, tetrodotoxin, a selective blocker of fast sodium channels, which prevents the formation of action potentials, does not interfere with TH induction mediated by carbamylcholine or nicotine. It is concluded that specific TH induction is mediated via nicotinic receptors by a mechanism which is not dependent on the activation of the fast sodium channels.
Otten
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Department of Pharmacology, Biocenter of the University, Basel, Switzerland.
Thoenen
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