GALANIN INHIBITS THE POTASSIUM-EVOKED RELEASE OF ACETYLCHOLINE AND THE MUSCARINIC RECEPTOR-MEDIATED STIMULATION OF PHOSPHOINOSITIDE TURNOVER IN SLICES OF MONKEY HIPPOCAMPUS

In the ventral hippocampus of Cynomologus monkey, galanin, a 29 amino acid long neuropeptide, reduced the potassium-evoked release of [H-3]acetylcholine from slices preloaded with [H-3]choline and diminished the carbachol-stimulated accumulation of [H-3]inositol polyphosphates in hippocampal microprisms preincubated with myo-[2-H-3]inositol. Using receptor autoradiography a strong, specific binding of iodinated galanin was observed in the molecular layer of the dentate gyrus. These may thus be the sites where galanin exerts its inhibitory effects on acetylcholine (ACh) release and phosphoinositide breakdown. These data provide evidence that galanin is a modulator of cholinergic function in septo-hippocampal neurons of primates.