Abstract
Purpose :
Epinephrine in intraocular irrigation solution is used to maintain mydriasis during surgery. Because a recent study reported that intravitreal infusion containing epinephrine decreased the optic nerve head blood flow during vitreous surgery, epinephrine may affect ocular blood flow during vitrectomy. However, the mechanism of the effect of epinephrine on the retinal microcirculation remains unclear. We examined the effects of epinephrine on the retinal microvasculature and investigated the signaling mechanisms involved in this vasomotor activity.
Methods :
Porcine retinal arterioles were isolated, cannulated, and pressurized (55 cmH2O) without flow for this in vitro study. Videomicroscopic techniques were used to record the changes in diameter in the retinal arterioles in response to epinephrine at concentrations of 0.1 nM to 1.0µM.
Results :
The retinal arterioles constricted in response to epinephrine in a concentration-dependent manner. Endothelial denudation did not suppress the vasoconstriction. Epinephrine-induced constriction was significantly (P<0.0001) suppressed by pretreatment with an alpha-1 adrenergic receptor blocker (0.1 µM) but not an alpha-2 or a beta adrenergic receptor blocker.
Conclusions :
The current findings suggested the importance of the effect of epinephrine in irrigation solution, i.e., constriction of retinal arterioles during vitrectomy.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.