GABAA and GABAB 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 membrane of rat neocortical layer V pyramidal neurons we used patch-clamp recording in combination with infrared-guided laser stimulation to release gamma-aminobutyric acid (GABA) photolytically. The data strongly suggest that relatively more GABA(A) receptors are located at the apical dendrite and relatively 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-mediated inhibitory postsynaptic potentials (IPSPs).