Hypertonic KCI, NaCI and capsaicin intracamerally causes release of substance P‐like immunoreactive material into the aqueous humor in rabbits

Abstract

The release of substance P[SP]-like immunoreactivity (SPLI) into the anterior chamber of the rabbit eye evoked by stimuli which cause non-cholinergic miosis was investigated. In a recent study such miosis was reported to be blocked by the substance P analog (D-Arg1. D-Pro2, D-Trp7.9, Leu11)-SP. Mechanical intracranial antidromic trigeminal nerve stimulation caused marked SPLI release presumably from primary sensory nerve endings in the anterior part of the eye. Intermittent stimulation for 20 min was not more effective than stimulation for 10 min. Intracameral injection of either 20 .mu.l 4.65 M KCl, 20 .mu.l 4.65 M NaCl or 100 .mu.g capsaicin also caused SPLI release. Intracameral injection of 70 .mu.l 150 mM KCl, 28 .mu.g prostaglandin E1 or 200 .mu.g of compound 48 80 [4-methoxy-N-methyldenzenoethanamine] did not cause detectable SPLI release.