Parasympathetic nervous control of intraocular pressure

Role of Muscarinic Cholinergic Transmission in Edinger-Westphal Nucleus-induced Choroidal Vasodilation in Pigeon

“…Our overall findings are consistent with the previously reported observations that the nonselective muscarinic antagonist atropine but not the M2 selective antagonist gallamine attenuates increases in intraocular pressure evoked by electrical stimulation of the oculomotor complex in cats (Gherezghiher, Hey and Koss, 1990). Such an increase in intraocular pressure is thought to be due to the choroidal vasodilation elicited by stimulation of parasympathetic input to eye (Bill, Stjernschantz and Alm, 1976 ;Gherezghiher, Hey and Koss, 1990). Atropine has been also reported to inhibit methacholine-induced uveal vasodilation in cats (Okubo, Gherezhiher and Koss, 1990), which is thought to be mediated via M3 muscarinic receptors (Koss, 1997).…”

“…The parallels between the effects of muscarinic antagonists on cholinergic vasodilation in the choroid of pigeon and the uvea of cat (Gherezghiher, Hey and Koss, 1990 ;Okubo, Gherezhiher and Koss, 1990) or the parotid gland of rat (Tobin, 1998) suggest that the muscarinic mechanisms of cholinergic vasodilation are similar in mammals and birds. While M3-selective antagonists and nonselective muscarinic antagonists attenuate the increases in blood flow elicited by parasympathetic activation in choroid and parotid gland, based on findings in the human upper limb (Bruning et al, 1994) and our current findings in pigeons, such drugs do not appear to significantly affect basal blood flow.…”

Autonomic Control of the Eye

“…In contrast, in mammals, based on anatomical studies, the parasympathetic innervation of the choroid arises primarily from the pterygopalatine ganglion (306, 318). However, physiological studies in mammals also suggest a contribution from the oculomotor nerve by way of the ciliary ganglion (122, 260). For example, electrical microstimulation of the Edinger-Westphal nucleus or the ciliary nerves has been shown to evoke increases in choroidal blood flow in the cat (e.g.…”

“…For example, electrical microstimulation of the Edinger-Westphal nucleus or the ciliary nerves has been shown to evoke increases in choroidal blood flow in the cat (e.g. 122, 260, 358) and the rabbit (e.g. 357).…”

Influence of Ophthalmic Nerve Fibers on Choroidal Blood Flow and Myopic Eye Growth in Chicks

“…The latter appear to exert their vasodilatory effect as a local response to peripheral stimulation under some circumstances (Holzer, 1988). The anatomical organization of these intrachoroidal nerve fibers, the transmitters they utilize and their influence on choroidal blood flow have been extensively studied in mammals (Ruskell, 1971 ;Bill, Stjernschantz and Alm, 1976 ;Butler et al, 1984 ;Stone, Kuwayama and Laties, 1987 ;Lin, Grimes and Stone, 1988 ;Gherezghiher, Hey and Koss, 1990 ;Bill, 1991 ;Deussen, Sonntag and Vogel, 1993 ;Yamamoto et al, 1993 ;Nilsson, 1994 ;Mann et al, 1995 ;Nakanome et al, 1995). In contrast, while the anatomy and function of the parasympathetic input to the choroid has been studied in birds (Gienc and Kuder, 1985 ;Meriney and Pilar, 1987 ;Fitzgerald, Vana and Reiner, 1990 a ;Fitzgerald et al, 1996 ;Sun, Erichsen and May, 1994 ;Bergua, Mayer and Neuhuber, 1996 ;Cuthbertson et al, 1996Cuthbertson et al, , 1997Zagvazdin et al, 1996), little functional information on the sensory innervation of the choroid is available for birds.…”