Calbindin‐immunoreactive neurones in the ovine rumen

Abstract

In small laboratory animals, such as guinea pigs, immunoreactivity for the calcium-binding protein calbindin (CALB) can be used to distinguish functionally different classes of myenteric neurones. The rumen of sheep is a highly specialized gastrointestinal region, and the control of its functions requires specific intrinsic innervation patterns. The aim of this study was to neurochemically identify and characterize CALB-positive myenteric neurones of the ovine rumen. Therefore, we performed quadruple immunohistochemistry against CALB, substance P (SP), vasoactive intestinal peptide (VIP), and nitric oxide synthase (NOS) using whole-mount preparations of the ruminal myenteric plexus. On average, 3 Ϯ 2 and 1 Ϯ 0.4 myenteric neurones/ganglion were CALB-immunoreactive in suckling lambs and adult sheep, respectively. These neurones had Dogiel type-I morphology. Most of them (89.2% Ϯ 8.7% and 71.7% Ϯ44.8% in suckling lambs and adult sheep, respectively) did not colocalize any of the other antigenes. Since it has been shown in previous studies that ruminal myenteric neurones are immunoreactive for either choline acetyltransferase (ChAT) or NOS, we defined neurones which were CALB-positive and NOS-negative as CALB/ChAT. The other CALB-positive neurones were encoded CALB/NOS/ϮVIP (10.3% Ϯ 9.3% and 26.7% Ϯ 46.2% in suckling lambs and adult sheep, respectively) or CALB/ChAT/SP (0.5% Ϯ 1.0% and 1.7% Ϯ 1.9% in suckling lambs and adult sheep, respectively). We used cryostat sections of the ruminal wall to analyze the projections of the CALB-positive neurones. CALB-immunoreactive somata were exclusively located within the myenteric plexus. CALB-immunoreactive nerve fibers were found primarily in the lamina propria of the ruminal papillae. We conclude that CALB-positive myenteric neurones within the ovine rumen project to the epithelium; however, their functional role remains to be investigated. Anat Rec Part A 278A: 528-532, 2004.

Intrinsic ruminal innervation in ruminants of different feeding types

“…In the sheep rumen, more than 80% of CALB immunoreactive neurons were SP negative. This finding is in accordance with results from previous studies in sheep (Pfannkuche et al. 2004a).…”

“…This is consistent with our finding that in cattle the majority of CALB immunoreactive neurons co‐localize with SP. We have previously suggested that CALB‐positive neurons may project to the ovine ruminal epithelium, although these neurons did not have morphological characteristics of intrinsic afferent neurons (Pfannkuche et al. 2004a).…”

Prenatal histomorphological development of the reticulum in fallow deer (Dama dama)

“…Moreover, reticulum with the rumen is considered as a one functional chamber (Kitamura, Yamada, & Yamashita, 1986). They take part in mixing and fermentation of the ingesta and they need specific motility patters (Pfannkuche, Schellhorn, Schemann, & Gäbel, 2004) that are under control by the neurons of enteric nervous system by releasing excitatory and inhibitory neurotransmitters (Groenewald, 1994;Kitamura et al, 1986;Münnich, Gäbel, & Pfannkuche, 2008). These specific motility patterns can be recorded in the reticulum before birth, although they disappear in the newborn (Ruckebusch, Dardillat & Guilloteau, 1983).…”

Intrinsic Innervation of the Persian Squirrel (Sciurus anomalus) Ileum

“…Most morphological, electrophysiological and neurochemical investigations on the ENS have been carried out on laboratory rodents such as the guinea pig (Mawe et al., ; Quinson et al., ; Furness et al., ), mouse (Qu et al., ; Mongardi Fantaguzzi et al., ), rat (Sayegh and Ritter, ; Mitsui, , ), hamster (Toole et al., , ), but also on some domestic large mammals such as the horse (Domeneghini et al., ; Freytag et al., ; Chiocchetti et al., ; Russo et al., ), pig (Brehmer and Stach, ; Brehmer et al., , ; Balemba et al., ), dog (Furness et al., ; Sternini et al., ), cat (Kleinschmidt et al., ), sheep (Chiocchetti et al., ; Pfannkuche et al., ; Mazzuoli et al., , ), and other small mammals, such as the rabbit (Gábriel et al., ; Dénes and Gábriel, ) and ferret (Sann et al., ), considering, at present, the latter species as domestic animals.…”