Acetylcholine, an inhibitory transmitter in the rat lateral hypothalamus

Basolateral stimulation of the amygdala inhibited spontaneous firing of rat lateral hypothalamic neurons. The inhibition was augmented by eserine and blocked by atropine. Acetylcholine mimicked the inhibition and produced approximately 15 mV of hyperpolarization beyond the original resting membrane potential which stopped spontaneous firing. The ACh effects were reversible. Results indicate that ACh might be an inhibitory transmitter involved in LH inhibition by AL stimulation.