The transduction mechanisms underlying presynaptic GABAB receptor-mediated inhibition of transmitter release have been characterized for a variety of synapses in the central nervous system (CNS). These studies have suggested a range of transduction mechanisms, including a role for second messengers such as protein kinases A (PKA) and C ( @entity6164 ). In the present study, we have examined the intracellular signalling pathways underlying @entity1772 -induced inhibition of @entity1246 release from terminals synapsing onto @entity35 basalis of Meynert neurons using patch-clamp recordings. @entity1772 , a selective GABAB receptor agonist, reversibly decreased both evoked and spontaneous, miniature, GABAergic inhibitory postsynaptic currents (eIPSCs and mIPSCs, respectively). Such @entity1772 actions were completely abolished by @entity7234 , a selective GABAB receptor antagonist, and by @entity866 , a non-selective PKA and @entity6164 inhibitor. The mIPSC frequency was still decreased by @entity1772 even in the presence of 4 AP, a K+ channel blocker, and @entity3280 , a voltage-dependent @entity460 channel blocker. Pharmacological activation or inhibition of @entity6164 activity affected basal @entity1246 release and mildly affected the response to @entity1772 . Inhibition of the @entity268 /PKA cascade also affected basal @entity1246 release and, in a subset of neurons, occluded the effects of @entity1772 , suggesting that the GABAB receptor-mediated inhibitory action on @entity1246 release was mediated via decreases in PKA activity. In addition, PKA inhibition occluded the effects of @entity6164 modulation on both basal @entity1246 release and on the response to @entity1772 . Our results characterize the transduction pathway of @entity1772 at these nucleus basalis of Maynert (nBM) synapses and show, for the first time, some cross-talk between the @entity268 /PKA and @entity6164 pathways in @entity1 presynaptic nerve terminals.

GABAB receptor transduction mechanisms, and cross-talk between protein kinases A and C, in GABAergic terminals synapsing onto neurons of the XXXX nucleus basalis of Meynert.

@entity268 :: ('CHEBI:17489', 'Chemical') :: ['cAMP'] @entity1 :: ('9606', 'Species') :: ['mammalian'] @entity1246 :: ('MESH:D005680', 'Chemical') :: ['GABA'] @entity7234 :: ('MESH:C085075', 'Chemical') :: ['CGP55845A'] @entity3280 :: ('CHEBI:48775', 'Chemical') :: ['Cd2+'] @entity866 :: ('MESH:D019311', 'Chemical') :: ['staurosporine'] @entity6164 :: ('MESH:C566847', 'Disease') :: ['PKC'] @entity460 :: ('MESH:D002118', 'Chemical') :: ['calcium'] @entity35 :: ('10116', 'Species') :: ['rat'] @entity1772 :: ('MESH:D001418', 'Chemical') :: ['Baclofen', 'baclofen']
@entity35 :: (10116,Species) :: ['rat']
