Effects of 6-hydroxydopamine and alpha-methyl-para-tyrosine on the acoustic startle response in rats.
The acoustic startle response was measured in rats after depletion of central catecholamines either chronically (through intraventricular injection of 6-hydroxydopamine) or acutely (through intraperitoneal injections of alpha-methyl-para-tyrosine). Chronic depletion resulted in an augmented startle response which could not be attributed to a failure of habituation or enhanced sensitization, while acute depletion depressed startle amplitude. The results were interpreted as evidence that catecholamines normally exert a facilitatory influence on the startle response and that the enhanced response seen in the chronically lesioned animal reflects the potentiation of the role of catecholamine-containing neurons through the development of denervation supersensitivity. This interpretation is consistent with other observations which suggest that catecholamines play a general role in modulating thresholds to aversive events.
D000161:Acoustic Stimulation; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D002395:Catecholamines / Q000378:metabolism; D006185:Habituation, Psychophysiologic / Q000187:drug effects; D006892:Hydroxydopamines / Q000494:pharmacology*; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology*; D051381:Rats; D013216:Reflex, Startle / Q000187:drug effects*; D013268:Stimulation, Chemical
D002395:Catecholamines; D006892:Hydroxydopamines; D008781:Methyltyrosines