Effects of protein kinase C inhibitor H-7 on membrane properties and synaptic responses of neocortical neurons of awake cats

• Published in: Brain research Vol. 506; no. 2; p. 281
• Main Authors: Szente, M B, Baranyi, A, Woody, C D
• Format: Journal Article
• Language: English
• Published: Netherlands 08-01-1990
• Subjects: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Action Potentials - drug effects; Animals; Cats; Cerebral Cortex - drug effects; Cerebral Cortex - physiology; Isoquinolines - pharmacology; Membrane Potentials - drug effects; Neural Inhibition - drug effects; Piperazines - pharmacology; Protease Inhibitors - pharmacology; Protein Kinase C - metabolism
• ISSN: 0006-8993
• DOI: 10.1016/0006-8993(90)91262-F

Electrophysiological effects of intracellularly pressure-injected H-7, an inhibitor of protein kinase C, were investigated in neocortical neurons of awake cats. H-7 reduced spontaneous and depolarizing current-induced firing activity and increased the latency and apparent threshold of action potentials elicited by depolarizing currents. Slow afterhyperpolarizations following action potentials and depolarizing pulses increased after injection of H-7, without detectable changes in the time course of the fast components of the action potentials. H-7 induced increases in IPSPs evoked by stimulation of the ventrolateral thalamus (VL) or the pyramidal tract (PT). Besides slight increases in the amplitude of IPSPs measured at peak, H-7 induced pronounced increases in the amplitude measured 50-100 ms after stimulation and in the total duration of IPSPs. EPSPs evoked by VL or PT stimulation did not show measurable alterations after injection of H-7. The effects occurred 2-15 min after injection of H-7 and lasted at least 90 min without essential changes in the baseline values of resting membrane potential or input resistance. The results suggest that in addition to playing a role in regulating membrane excitability, protein kinase C influences the inhibitory synaptic mechanisms of neocortical neurons.