Repeated cocaine administration increases membrane excitability of pyramidal neurons in the rat medial prefrontal cortex

NASIF, FERNANDO J.

JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS

AMER SOC PHARMACOLOGY EXPERIMENTAL THERAPEUTICS

Año: 2005 vol. 312 p. 1305 - 1305

0022-3565

lthough the medial prefrontal cortex (mPFC) plays a critical role in cocaine addiction, the effects of chronic cocaine on mPFC neurons remain poorly understood. Here, we performed visualized current-clamp recordings to determine the effects of repeated cocaine administration on the membrane excitability of mPFC pyramidal neurons in rat brain slices. Following repeated cocaine administration (15 mg/kg/day i.p. for 5 days) with a 3-day withdrawal, alterations in membrane properties, including increased input resistance, reduced intensity of intracellular injected currents required for generation of Na+-dependent spikes (rheobase), and an increased number of spikes evoked by depolarizing current pulses were observed in mPFC neurons. The current-voltage relationship was also altered in cocaine-pretreated neurons showing reduced outward rectification during membrane depolarization and decreased inward rectification during membrane hyperpolarization. Application of the K+ channel blocker Ba