Norepinephrine causes a biphasic change in mammalian pinealocye membrane potential: role of alpha1B-adrenoreceptors, phospholipase C, and Ca2+.

ABSTRACT: Perforated patch clamp recording was used to study the control of membrane potential (V(m)) and spontaneous electrical activity in the rat pinealocyte by norepinephrine. Norepinephrine did not alter spiking frequency. However, it was found to act through α(1B)-adrenoreceptors in a concentration-dependent manner (0.1-10 μM) to produce a biphasic change in V(m). The initial response was a hyperpolarization (∼13 mV from a resting potential of -46 mV) due to a transient (∼5 sec) outward K(+) current (∼50 pA). This current appears to be triggered by Ca(2+) released from intracellular stores, based on the observation that it was also seen in cells bathed in Ca(2+)-deficient medium. In addition, pharmacological studies indicate that this current was dependent on phospholipase C (PLC) activation a

SUBMITTER: Zemkova H 

PROVIDER: S-EPMC3176642 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature