Galanin and calcitonin gene-related peptide immunoreactivity in nerves of the rat uterus: Localization, colocalization, and effects on uterine contractility

Abstract

Immunoreactivity to the neuropeptides galanin (GAL) and calcitonin gene-related peptide (CGRP) was examined in nerves in the rat uterus as a prelude to studying their effects on uterine contractility. With immunocytochemical techniques, GAL immunoreactivity (GAL-I) and CGRP-I were localized in myometrial nerves throughout the uterine horns and cervix, with nerves immunoreactive for CGRP being more numerous. Immunocytochemical double-labeling studies revealed GAL coexists with CGRP in a subpopulation of CGRP-I nerve fibers, i.e., GAL-I was not present in all CGRP-I nerves. Effects of these neuropeptides on uterine contractility were examined on in vitro preparations of uterine horns from diethylstilbestrol-treated rats. GAL (10(-5) to 10(-8) M) stimulated uterine contraction in a dose-related manner. CGRP had no effect on basal uterine tension, but CGRP (10(-7) M) reduced GAL-stimulated (10(-7) M) uterine contraction by 92.5%. These results demonstrate that GAL- and CGRP-I are present in, and coexist in, some uterine nerves, presumably afferent nerves. GAL and CGRP could be released from afferent fibers in an "efferent fashion" and influence uterine contractility, GAL having a contractile effect and CGRP having a relaxing effect.

Pregnancy-induced uterine neuronal degeneration in the rat

“…Shew et al (1992), while observing many fibers along blood vessels, reported more nonvascular CGRP-immunoreactive fibers than observed in our material. The role of uterine CGRP-immunoreactive fibers, and the possible distinction between the vascular and nonvascular CGRP-immunoreactive fibers, is unclear.…”

“…We would not have expected to find preganglionic efferent axons in the body of the uterus, and these would have been the only source of efferent CGRP-immunoreactive fibers. Indeed, Shew and coworkers (Shew et al 1991(Shew et al , 1992 reviewed the evidence that CGRP-immunoreactive fibers in the uterus are restricted to axons of primary afferent neurons, and they found it convincing.…”

Innervation of the rat uterus at estrus: A study in full‐thickness, immunoperoxidase‐stained whole‐mount preparations

“…SP contracts the smooth muscle of the myometrium and dilates uterine blood vessels Traurig and Papka, 1993). CGRP relaxes myometrial smooth muscle (Shew et al, 1990(Shew et al, , 1992Traurig and Papka, 1993) and myometrial contractions in the uterus of rats and humans are inhibited by CGRP Yallampalli et al, 2002;Gangula et al, 2003). CGRP is also a vasodilator of uterine vasculature (Gangula et al, 2003;Mowa et al, 2003).…”

Mechanisms underlying the neurokinin A‐induced contraction of the pregnant rat myometrium

“…Since NKA-containing ®bres innervate the uterus of various species (Gibbons et al, 1985;Shew et al, 1992;Traurig et al, 1988), it can be postulated that NKA might have a role in the regulation of the uterine function, especially in pregnancy. This speculation is supported by the following reports: (1) The pelvic neurectomies lead to uterine dystocia in the pregnant rat (Higuchi et al, 1987;Traurig et al, 1984;, and aerent C-®bres may play a role in the neural regulation of parturition (Traurig et al, 1991); (2) NKA induced contractions in the rat myometrial strips (Fisher & Pennefather, 1997;Fisher et al, 1993;Pennefather et al, 1993) and (3) NK-2 receptor, which is preferentially activated by NKA, were predominant in the estrogen-primed rat myometrium (Fisher & Pennefather, 1998;1999;Fisher et al, 1993;Magraner et al, 1998;.…”