Cerebrovascular evidence for a GABAergic modulation of the cholinergic vasodilatatory basalocortical system in the rat

The present work is aimed to study the functional relevance of GABAergic-cholinergic interactions on the modulation of cerebral blood flow (CBF) exerted by the basalocortical system. Injections of GABA into the substantia innominata (SI) induce increases in blood flow in several cortical areas and inhibit partly the increases in cortical blood flow induced by cholinergic activation of this structure. Blockade of local GABAergic receptors by picrotoxin induced almost similar effects. These findings suggest that local GABAergic neurones of the SI exert a complex cortical cerebrovascular modulation at a resting and an activated state.