Involvement of Ca²⁺ in Signaling Mechanisms Mediating Muscarinic Inhibition of M Currents in Sympathetic Neurons.

ABSTRACT: Acetylcholine can excite neurons by suppressing M-type (KCNQ) potassium channels. This effect is mediated by M₁ muscarinic receptors coupled to the G_q protein. Although PIP₂ depletion and PKC activation have been strongly suggested to contribute to muscarinic inhibition of M currents (I_M), direct evidence is lacking. We investigated the mechanism involved in muscarinic inhibition of I_M with Ca²⁺ measurement and electrophysiological studies in both neuronal (rat sympathetic neurons) and heterologous (HEK cells expressing KCNQ2/KCNQ3) preparations. We found that muscarinic inhibition of I_M was not blocked either by PIP₂ or by calphostin C, a PKC inhibitor. We then examined whether muscarinic inhibition of

SUBMITTER: Yoon JY 

PROVIDER: S-EPMC10287826 | biostudies-literature | 2023 Jul

REPOSITORIES: biostudies-literature