GABA(A) and GABA(B) receptors on neocortical neurons are differentially distributed

The distribution of functional neurotransmitter receptors on the surface of neurons is highly relevant for synaptic transmission and signal processing . To map functional GABA(A) and GABA(B) receptors on the somadendritic memb rane of rat neocortical layer V pyramidal neurons we used patch-clamp recor ding in combination with infrared-guided laser stimulation to release gamma -aminobutyric acid (GABA) photolytically. The data strongly suggest that r elatively more GABA(A) receptors are located at the apical dendrite and rel atively more GABA(B) receptors near the soma. Such a specific distribution of GABA(A) and GABA(B) receptors may serve to compensate for differences in electrotonic voltage attenuation between GABA(A) and GABA(B) receptor-medi ated inhibitory postsynaptic potentials (IPSPs).