[A pharmacological analysis of pentagastrin-modulated behavior evoked by stimulation of the ventromedial hypothalamus].

The purpose of the present investigations was to examine the neurochemical mechanisms of modulatory effect of pentagastrin (PG) on escape reaction elicited by the threshold electrical stimulation of the ventromedial hypothalamus (VMH) in rabbits. PG administration (35 mcg/kg intraventricularly) was found to transform escape into feeding. This phenomenon was shown to begin at 20 min and to last to 150 min after PG injection. The animals were treated with various antagonists to some classic neurotransmitters of the central nervous system. Kalipsol (0.25, 0.5 mg/kg intravenously) and ketanserin (0.1 mg/kg intravenously) were found to restore feeding into escape. GABA-ergic antagonist baclofen (0.25, 0.5 mg/kg) was demonstrated to shorten to about 30 min the time of feeding after PG administration. Both inderal-beta-adreno-blocker (0.25, 0.5, 1.0 mg/kg) and M-choline antagonist atropine (0.25, 0.5 mg/kg) were found to be ineffective in escape restoration in response to VMH stimulation. The experimental results suggest the important role of N-cholinergic and serotoninergic brain structures in PG transformation of escape elicited from the VMH into feeding.