Calbindin-immunopositive cells are cholinergic interneurons in the myenteric plexus of rabbit ileum

Abstract

The 28-kDa calcium-binding protein (calbindin) is a widely studied neuronal marker in the enteric nervous system of numerous species. Calbindin has previously been detected in myenteric neurons of rabbit ileum in which 3% of all myenteric neurons are calbindin-immunopositive. We have studied the detailed morphology and chemical coding of calbindin-immunopositive neurons in this segment of the gut. We have found calbindin immunoreactivity in both strongly and weakly stained neurons. Of these, the strongly immunoreactive neurons belong to the Dogiel type I category. These neurons project only to other ganglia and primary strands of the plexus and their processes never run to the muscle or mucosal layers. The neurons within this group are 29.5+/-6.6 microm in length and 14.7+/-3.8 microm in width. The second smaller group of immunoreactive cells (27%) label faintly and have different morphological properties. They are characterized by their round medium-sized cell bodies (long axis: 24.4+/-5.2 microm; short axis: 15.5+/-2.9 microm) and do not exhibit immunoreactivity either in their dendrites or in their axonal processes. Double-label studies show that all calbindin-immunopositive neurons lack immunoreactivity for nitric oxide synthase, vasoactive intestinal peptide and substance P but all are immunoreactive for the synthesizing enzyme of acetylcholine, choline acetyltransferase. Thus, populations of neurons containing calbindin are cholinergic interneurons in the myenteric plexus of rabbit ileum.

Zinc Transporter 3 (Znt3) as an Active Substance in the Enteric Nervous System of the Porcine Esophagus

“…Important functions of acetylcholine in physiology of the GI tract are confirmed by its presence in various classes of enteric neuronal cells, such as intrinsic primary afferent neurons, ascending and descending enteric interneurons, motoneurons, and intestinofugal afferent neurons (Li and Furness 1998; Dénes and Gábriel 2004; Furness 2012; Chen et al 2014). …”

The chemical code of porcine enteric neurons and the number of enteric glial cells are altered by dietary probiotics

“…In humans, 28 and in large mammalian species, 9,29 the enteric cholinergic neurons account for 50–70% of enteric neurons, whereas in laboratory animals (guinea‐pig) their number is larger (around 80% in the small intestine) 4 . The fact that the cholinergic neurons in both the ileum and cecum out‐numbered the intramural neurons shown by the PGP 9.5 neuronal marker is possibly due to technical aspects, because the effective possibility of revealing neurons by the so‐called pan neuronal markers may vary in different species and localizations 30 . We did not observe catecholaminergic neurons, unlike Li et al.…”

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.…”