Modulation of the acoustic startle reflex by infusion of corticotropin-releasing hormone into the nucleus reticularis pontis caudalis.
The amplitude of the acoustic startle reflex can be modulated by exposure to aversive stimuli or other conditions which evoke a state of fear. The neurotransmitters involved in this modulation are currently being investigated. Unilateral local infusion of corticotropin-releasing hormone (CRH; 0, 10, 20, 40 and 80 ng) into the nucleus reticularis pontis caudalis (PnC), an obligatory synapse in the acoustic startle reflex, significantly elevated startle amplitude in a dose-dependent manner. The facilitation of startle began immediately following infusion, reached asymptote approximately 20-25 min later, and persisted throughout the remaining 60 min test session. This CRH-enhanced startle effect was blocked by infusion of the CRH antagonist, alpha-helical CRH9-41, immediately prior to CRH infusion. These results support an involvement of CRH at the level of the PnC in modulating the acoustic startle reflex.
Birnbaum
S G
SG
Interdept. Neuroscience Program, Yale University School of Medicine, Connecticut Mental Health Center, New Haven 06508, USA. shari.birnbaum@yale.edu
Davis
M
M
D000161:Acoustic Stimulation; D000818:Animals; D001931:Brain Mapping; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006727:Hormone Antagonists / Q000494:pharmacology; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology; D011149:Pons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013216:Reflex, Startle / Q000187:drug effects* / Q000502:physiology
D006727:Hormone Antagonists; D010446:Peptide Fragments; D003346:Corticotropin-Releasing Hormone; C045089:corticotropin releasing hormone (9-41)