GABA and hypothalamic feeding systems. II. A comparison of GABA, glycine and actylcholine agonists and their antagonists.

Microinjections of various compounds into the paraventricular hypothalamic nucleus (PVH) were made and the effects on feeding observed. During the light phase of the lighting cycle, injections of 0.3 microliter of muscimol (100 ng) and flurazepam diHCl (20 micrograms) increased feeding. Similar injections of glycine (500 ng) did not influence feeding during the light phase. During the dark phase, 0.3 microliter injections of bicuculline methiodide (30 ng) and picrotoxin (160 ng) suppressed feeding. Similar i-jections of carbachol increased drinking during the dark phase. Injections of strychnine during this phase were without effect. Tilt box activity levels were not altered by injection of picrotoxin (160 ng) into the PVH.