Membrane mechanism associated with muscarinic receptor activation in single cells freshly dispersed from the XXXX anococcygeus muscle.

@entity3897 @entity2865 @entity35 @entity1063 @entity5402
1 The mechanism of action of @entity5402 was studied on freshly dispersed cells of the @entity35 anococcygeus using microelectrodes and patch pipettes. 2 Micro-ionophoretic application of @entity5402 evoked reproducible depolarizations which were reduced or blocked by @entity3897 (10(-7)-10(-6) M). The time courses of the responses to @entity1063 and @entity5402 were similar. 3 The reversal potential of the @entity5402 -induced response was -3.8 mV and similar to the value (-6.2 mV) found for @entity1063 . 4 During the response to @entity5402 the membrane conductance was increased. At depolarized membrane potentials @entity5402 evoked biphasic membrane responses suggesting an increase in two separate ionic conductances. 5 With patch pipettes in the whole-cell configuration under voltage-clamp, @entity5402 produced an inward current at a holding potential of -50 mV. The inward current was associated with an increase in membrane conductance with an equilibrium potential of about 0 mV. 6 It is suggested that muscarinic receptors and adrenoceptors in the @entity35 anococcygeus may activate similar membrane conductances. The most prominent mechanism is an increase in @entity2865 ion conductance.
