PROTEIN-KINASE A-DEPENDENT INCREASE IN FREQUENCY OF MINIATURE GABAERGIC CURRENTS IN RAT CA3 HIPPOCAMPAL-NEURONS

The whole-cell configuration of the patch clamp technique was used to study the effect of an intracellular increase in cAMP on the frequency of GABA-mediated miniature post synaptic currents (MPSCs) in neonatal rats from (P6 to P12) CA3 hippocampal neurons in slices. In the prese nce of tetrodotoxin (1 mu M), and kynurenic acid (1 mM) to block ionot ropic glutamatergic currents, forskolin, an activator of adenylate cyc lase, markedly increased the frequency of MPSCs without affecting thei r amplitude or kinetics. The inactive forskolin analog, 1,9-dideoxyfor skolin (30 mu M), had no effect on the frequency of MPSCs. The effect of forskolin was prevented by the specific protein kinase A (PKA) anta gonist Rp-cAMP (30 mu M). It is concluded that stimulation of PKA pote ntiates spontaneous GABA release in immature hippocampal neurons.