Evidence That Adrenaline Is Released From Adrenergic Neurones in the Rectum of the Fowl

Abstract

The rectum isolated from the fowl was perfused with Tyrode solution via the caudal mesenteric artery. Noradrenaline and adrenaline were biologically or fluorimetrically assayed in perfusates collected before and during stimulation of Remak's nerve or of the periarterial nerves. Perfusates collected during nerve stimulation relaxed the chick rectum and rat stomach strips which served as assay tissues. This effect was attributed to the action of noradrenaline or adrenaline released from adrenergic nerve endings which appeared in the perfusates. Perfusates obtained during stimulation (30 Hz for 60 s) of Remak's nerve contained both noradrenaline and adrenaline when measured fluorimetrically. The mean output per stimulus train was 0.8 ± 0.2 ng/g wet wt. tissue for noradrenaline and 1.7 ± 0.2 ng/g wet wt. tissue for adrenaline (n = 7). Perfusates obtained during stimulation (30 Hz for 60 s) of the periarterial nerves contained noradrenaline in a concentration of 1.6 ± 0.3 ng/g wet wt. tissue per stimulus train, but almost no adrenaline (n = 7). Neither stimulation of Remak's nerve nor the periarterial nerves liberated catecholamines when the rectum was perfused with Tyrode solution containing low Ca2+ (0.1 mm) and high Mg2+ (10 mm). Infusion of high potassium solution (50 mm) increased markedly the output of noradrenaline and adrenaline. Adrenaline as well as noradrenaline may function as the adrenergic neurotransmitter in the rectum of the fowl.

The EFFECTS OF Α‐ AND Β‐ADRENOCEPTOR ACTIVATION ON TENSION AND MEMBRANE PROPERTIES OF THE LONGITUDINAL SMOOTH MUSCLE OF THE CHICKEN RECTUM

“…In the rat heart, the uptake process has only about a two fold greater affinity for noradrenaline than adrenaline (Iversen, 1967). In the chicken rectum there is a 50 fold greater sensitivity to adrenaline than noradrenaline, yet blockade of uptake by phenoxybenzamine following stimulation of Remak's nerve increases the mean output of noradrenaline by only seven fold and that of adrenaline by three fold (Komori et al, 1979a). It appears unlikely therefore that the high sensitivity to adrenaline arises from an increased uptake and subsequent metabolism of noradrenaline.…”

“…High levels of adrenaline are present in the chicken rectum (Konaka, Ohashi, Okada & Takewaki, 1979) associated with Remak's nerve (Komori, Ohashi, Okada & Takewaki, 1979a). However, information about the pharmacological characteristics of the adrenoceptors in the effector cells which would promote an understanding of the function of the adrenergic nerves in the chicken rectum, is limited.…”

Nerve pathways involved in adrenergic regulation of electrical and mechanical activities in the chicken rectum

“…has been shown to be small or absent in intestinal smooth muscles (Bulbring et al, 1980). In chicken rectum, P-receptors are of the P2-type (Komori et al, 1980) and it has been demonstrated that preferential release of adrenaline rather than noradrenaline is elicited by stimulation of Remak's nerve trunk (Komori et al, 1979). Thus, this tissue is different from mammalian intestines in which pI-receptors are present (Lands et al, 1967) and noradrenaline functions as the neurotransmitter.…”

Cold stress initiates catecholaminergic and serotonergic responses in the chicken gut that are associated with functional shifts in the microbiome

“…The study of neurochemicals as interkingdom signaling molecules has been termed Microbial Endocrinology ( Neuman et al, 2015 ). Like in mammals, the avian intestinal tract is a major source of many monoamine neurochemicals ( Lyte et al, 2022 ) as it is highly innervated by the enteric nervous system and contains non-neuronal endocrine cell populations ( Komori et al, 1979 ; Rawdon, 1984 ). Another similarity between the mammalian and avian intestinal microbiota are several resident bacterial taxa that synthesize and respond to structurally identical neurochemicals of the host neuroendocrine system ( Villageliu and Lyte, 2017 ).…”