Corticotrophin-releasing hormone decreases synaptic transmission in rat sensorimotor cortex in vivo.
Corticotrophin-releasing hormone is a key regulator of the mammalian stress response. Although its actions on behavior are well documented, the actions of corticotrophin-releasing hormone in cortical neuronal systems are poorly understood. In the present experiments, adult male Sprague-Dawley rats were anesthetized and field excitatory post-synaptic potential recordings were made from sensorimotor cortex layer II/III and layer V cells. Infusions of corticotrophin-releasing hormone (100 ng/nl) directly into the sensorimotor cortex produced a significant depression of the initial excitatory component of evoked responses that could be prevented by prior administration of a corticotrophin-releasing hormone antagonist. Although requiring the activation of corticotrophin-releasing hormone receptors, the depression was also dependent upon N-methyl-D-aspartate receptor activity and could be blocked by the competitive N-methyl-D-aspartate antagonist -3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonate. These findings demonstrate that corticotrophin-releasing hormone has a novel depressant-like action in sensorimotor cortex in vivo that may play a role in modulating motor activity during periods of stress.
Froc
D J
DJ
Department of Psychology, the Neuroscience Program, and the Brain Research Centre, University of British Columbia, 2136 West Mall, Vancouver, British Columbia, Canada V6T 1Z4.
Christie
B R
BR
D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004347:Drug Interactions; D004558:Electric Stimulation / Q000379:methods; D004594:Electrophysiology / Q000379:methods; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D036881:Long-Term Synaptic Depression / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D008297:Male; D009044:Motor Cortex / Q000166:cytology*; D009474:Neurons / Q000187:drug effects*; D010879:Piperazines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D009435:Synaptic Transmission / Q000187:drug effects*; D013997:Time Factors
D018691:Excitatory Amino Acid Antagonists; D010879:Piperazines; D003346:Corticotropin-Releasing Hormone; C050592:3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid