Cannabinoid and Cannabinoid-Related Receptors in the Myenteric Plexus of the Porcine Ileum

Abstract

An important piece of evidence has shown that molecules acting on cannabinoid receptors influence gastrointestinal motility and induce beneficial effects on gastrointestinal inflammation and visceral pain. The aim of this investigation was to immunohistochemically localize the distribution of canonical cannabinoid receptor type 1 (CB1R) and type 2 (CB2R) and the cannabinoid-related receptors transient potential vanilloid receptor 1 (TRPV1), transient potential ankyrin receptor 1 (TRPA1), and serotonin receptor 5-HT1a (5-HT1aR) in the myenteric plexus (MP) of pig ileum. CB1R, TRPV1, TRPA1, and 5-HT1aR were expressed, with different intensities in the cytoplasm of MP neurons. For each receptor, the proportions of the immunoreactive neurons were evaluated using the anti-HuC/HuD antibody. These receptors were also localized on nerve fibers (CB1R, TRPA1), smooth muscle cells of tunica muscularis (CB1R, 5-HT1aR), and endothelial cells of blood vessels (TRPV1, TRPA1, 5-HT1aR). The nerve varicosities were also found to be immunoreactive for both TRPV1 and 5-HT1aR. No immunoreactivity was documented for CB2R. Cannabinoid and cannabinoid-related receptors herein investigated showed a wide distribution in the enteric neurons and nerve fibers of the pig MP. These results could provide an anatomical basis for additional research, supporting the therapeutic use of cannabinoid receptor agonists in relieving motility disorders in porcine enteropathies.

The cannabinoid receptors system in horses: Tissue distribution and cellular identification in skin

“…One study confirmed CBRs expression along the DRG sensory neurons 25 . Results of that study were consistent with previous observations in other species and those presented by other groups 21,22,45,46 . The DRG nerve terminals play a specific role in CBRs neurobiology and have been investigated in many aspects, mainly neuroinflammation 47 .…”

“… 25 Results of that study were consistent with previous observations in other species and those presented by other groups. 21 , 22 , 45 , 46 The DRG nerve terminals play a specific role in CBRs neurobiology and have been investigated in many aspects, mainly neuroinflammation. 47 Studies on rat peripheral tissues show that experimental sciatic nerve injury is an inducible factor for detecting CBRs at mRNA and protein levels.…”

“…18,19 These CBR-based treatments recently have attracted considerable attention in equine veterinary medicine after their use in other vertebrate species, including dogs, cats, and pigs. [20][21][22][23][24] Unfortunately, knowledge about the ECS in horses is still limited to dorsal root ganglion (DRG) neurons and equine genome sequencing analysis. [25][26][27][28] No studies on CBRs distribution and cellular expression in the cutaneous milieu are available.…”

Cannabis and Cannabis Derivatives for Abdominal Pain Management in Inflammatory Bowel Disease

“…CB 1 R is expressed throughout enteric nervous system cholinergic neurons, ascending and longitudinal muscle interneurons, and intrinsic primary afferent neurons [20,45]. CB 1 R is also expressed within intestinal mucosa enteroendocrine cells and enterocytes [45,47]. CB 2 R is also expressed on enterocytes as well as on neurons in the enteric nervous system [48,49].…”

Mutual Links between the Endocannabinoidome and the Gut Microbiome, with Special Reference to Companion Animals: A Nutritional Viewpoint

“…With regard to the GI tract, cannabinoid and cannabinoid-related receptors showed wide distribution in several mammals, including mice, pigs, ferrets, dogs, cats, horses and human beings [85][86][87][88][89][90][91][92][93][94][95][96][97][98]. In canine and feline species, CB1 receptor immunolabeling is mainly observed on enteric neurons, nerve fibers, gastric parietal cells, epithelial cells (including goblet cells and enteroendocrine cells) [90,[96][97][98].…”