Guinea pig medial vestibular nucleus neurons in vitro respond to ACTH4-10 at picomolar concentrations.
The responses of single guinea pig medial vestibular nucleus (MVN) neurons in vitro to adrenocorticotropic hormone, fragment 4-10 (ACTH4-10) were recorded extracellularly. In coronal slices and in the isolated MVN, neurons were found which responded to ACTH4-10 at picomolar concentrations (10(-12)M), indicating that ACTH4-10 acts directly on MVN neurons and suggesting the possibility that ACTH4-10 may act as a neurotransmitter in the MVN. In most cases where neurons responded to ACTH4-10 (37/74 neurons), the effect was a decrease in firing. Whether or not the depressive action of ACTH4-10 on the firing rate of MVN neurons in vitro is related to the acceleration of behavioral recovery from unilateral labyrinthectomy (vestibular compensation), which has been reported previously (Flohr and Luneburg 1982; Igarashi et al. 1985), is unclear.
Darlington
C L
CL
Department of Physiology, University of Otago, Dunedin, New Zealand.
Smith
P F
PF
Hubbard
J I
JI
D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008832:Microchemistry; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010446:Peptide Fragments / Q000494:pharmacology*; D013997:Time Factors; D014726:Vestibular Nuclei / Q000502:physiology*
D010446:Peptide Fragments; D000324:Adrenocorticotropic Hormone; C011394:ACTH (4-10)