Fear induced by the blockade of GABAA-ergic transmission in the hypothalamus of the cat: behavioral and neurochemical study.
Intrahypothalamic injections of d-Tubocurarine (DT) and bicuculline (BM) in the cat produced a fear reaction characterized by terrific mewing, increased locomotor activity, jumps and attempt to escape from the chamber, pupillary dilatation, increased respiratory rate, and sometimes urination and defecation. HPLC analysis showed a significant increase in the noradrenergic system activity in the emotional brain areas (hypothalamus, midbrain, amygdala) and frontal cortex at the time of the fear drive. No changes in the cat's behavior and in the monoaminergic systems activity occurred after muscimol+d-Tubocurarine injections into the hypothalamus. Similar behavioral and neurochemical effects evoked by DT and BM suggest that the fear response evoked by DT does not result from the blockade of N-cholinergic transmission but rather from their action on GABAA receptor complex. The results obtained indicate that the central triggering mechanism for fear drive depends on the blockade of GABAA-ergic transmission.
Strzelczuk
M
M
Department of Neurophysiology, University of Lódź, Poland.
Romaniuk
A
A
D000679:Amygdala / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001679:Biogenic Amines / Q000378:metabolism; D002415:Cats; D005239:Fear / Q000187:drug effects*; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism*; D007267:Injections; D008297:Male; D008636:Mesencephalon / Q000187:drug effects / Q000378:metabolism; D009043:Motor Activity / Q000187:drug effects; D018733:Nicotinic Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D017397:Prefrontal Cortex / Q000187:drug effects / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects*; D014403:Tubocurarine / Q000008:administration & dosage / Q000494:pharmacology; D014828:Vocalization, Animal / Q000187:drug effects
D001679:Biogenic Amines; D018756:GABA Antagonists; D058787:GABA-A Receptor Antagonists; D018733:Nicotinic Antagonists; D014403:Tubocurarine