Inhibition by MIF-I of alpha-MSH induced increase of intraocular pressure and miosis in rabbits.
The effects of intracameral (i.c.) administration of MIF-I on the ocular response to alpha-MSH were tested in rabbits. In confirmation of previous studies, i.c. alpha-MSH significantly increased intraocular pressure (IOP) and reduced pupillary diameter (PD). Concomitant administration of alpha-MSH and MIF-I antagonized both the IOP increase and miosis induced by alpha-MSH. Aqueous humor (AH) dynamics studies revealed that alpha-MSH increases IOP, possibly, by decreasing AH outflow. The decreased AH outflow induced by alpha-MSH was antagonized by concurrent administration of MIF-I and alpha-MSH. MIF-I did not affect IOP or PD when administered alone. These results add more support for a role of alpha-MSH in ocular function, and suggest that the ocular response to alpha-MSH may be subject to inhibitory control by MIF-I.
McCullen
R K
RK
Department of Ophthalmology, University of North Carolina School of Medicine, Chapel Hill 27514.
Peiffer
R L
RL
Jennes
L
L
Hernandez
D E
DE
D000818:Animals; D001082:Aqueous Humor / Q000187:drug effects*; D007429:Intraocular Pressure / Q000187:drug effects*; D009075:MSH Release-Inhibiting Hormone / Q000494:pharmacology*; D008297:Male; D011680:Pupil / Q000187:drug effects*; D011817:Rabbits; D000521:alpha-MSH / Q000494:pharmacology*
D000521:alpha-MSH; D009075:MSH Release-Inhibiting Hormone