Action of biologically active peptides on monkey iris sphincter and dilator muscles

Distribution of galanin receptors in the human eye

“…Sources of these nerve fibers are cranial autonomic ganglia: since human superior cervical ganglion lacks galaninergic neurons (Baffi et al, 1992) but galaninergic neurons are detected in human trigeminal ganglion (Del Fiacco and Quartu, 1994), it is likely that GAL is part of the primary afferent signal cascade in humans. In line with these observations is that GAL elicits no iris sphincter contraction in non-human primates in-vitro (Yamaji et al, 2005) and in-vivo (Almegard and Andersson, 1990). On the other hand, a GAL modulation or inhibition of the cholinergic transmission has been demonstrated for the isolated rabbit iris sphincter (Ekblad et al, 1985;Yamaji et al, 2003), however, the receptors responsible are unknown yet.…”

Pituitary adenylate cyclase activating polypeptide in the retina: focus on the retinoprotective effects

“…Both PACAP27 and –38 enhance cholinergic transmission in iris sphincter muscle, and PACAP27 induces relaxation of the dilator muscle 51 . The effect of PACAP on sphincter muscle response has also been shown in monkeys 52 . Intravitreal injection of PACAP induces hyperemia and mimicked the symptoms of ocular inflammation in the rabbit eye, indicating an involvement of PACAP in ocular inflammatory responses 33 .…”

Neuropeptide Y system in the retina: From localization to function

“…NPY-immunoreactive fibers surrounding iris blood vessels are abundant in rat and guinea pig, and innervate iris muscles, iris stroma and its melanocytes (Rittig et al, 1993). In addition, NPY attenuates the iris sphincter response to stimulation, but has no effect on monkey iris dilator muscle (Yamaji et al, 2005). Moreover, Stone and collaborators suggest a relationship between those NPY-fibers and the ciliary body melanocytes (Stone et al, 1986).…”

“…Research on the expression, localization and function of NPY in different regions of the eye started right after NPY discovery by Tatemoto (Bruun et al, 1984a(Bruun et al, , 1985(Bruun et al, , 1984bTatemoto et al, 1982). Since then, NPYimmunoreactivity (NPY-IR) has been detected in nerve fibers innervating several eye regions: anterior uvea, iris, choroid, ciliary body, ciliary epithelium, retinal cells, retinal vasculature, and others (Adeghate, 1996;Cavallotti et al, 2000;Jones and Marfurt, 1998;Lambiase et al, 2011;Nilsson, 1991;Paulsen et al, 2000;Rittig et al, 1993;Selbach et al, 2000Selbach et al, , 1998Stone et al, 1986;Trivino et al, 2005;Wetzel and Eldred, 1997;Yamaji et al, 2005;Ye et al, 1990). Thus, NPY-IR associated with sympathetic nerve fibers innervating all these areas indicates a putative role of NPY in the regulation of several aspects of eye physiology.…”