An in vitro investigation of the effects of the ACTH/MSH(4-9) analogue, Org 2766, on guinea pig medial vestibular nucleus neurons.
Vestibular compensation is a process of CNS plasticity that is correlated to a return of resting activity in medial vestibular nucleus (MVN) neurons ipsilateral to a peripheral vestibular deafferentation. Systemic administration of melanocortin peptides accelerates the compensation process; the ACTH/MSH(4-9) analogue, Org 2766, accelerates this process at smaller doses than ACTH/MSH(4-10). The present study investigated the effect of Org 2766 on MVN neurons in vitro using extracellular single-cell recording. Org 2766 was less potent at the neuronal level than ACTH/MSH(4-10). When Org 2766 and ACTH/MSH (4-10) were tested consecutively on the same neuron, the response was often different. Org 2766 and ACTH/MSH (4-10) may have a different mode and/or site of action.
Gilchrist
D P
DP
Department of Psychology, University of Otago, New Zealand.
Darlington
C L
CL
Smith
P F
PF
D000324:Adrenocorticotropic Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009473:Neuronal Plasticity; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010446:Peptide Fragments / Q000494:pharmacology*; D014726:Vestibular Nuclei / Q000502:physiology*
D000927:Anticonvulsants; D010446:Peptide Fragments; C013765:Org 2766; C028024:ACTH (4-9); D000324:Adrenocorticotropic Hormone; C011394:ACTH (4-10)