Myenteric neurons

Gelperin, D., Mann, D., Del Valle, J. and Wiley, J. Bradykinin (BK) increases cytosolic calcium in cultured rat myenteric neurons via BK-2 type receptors coupled to mobilization of extracellular and intracellular sources of calcium Evidence that calcium influx is prostaglandin dependent. /. Pharmacol. Exp. Ther. 271 507-514,1994. 

Gastrointestinal tract. Serotonin released from myenteric neurons or enterochromaffin cells acts on 5-HT3 and 5-HT4 receptors to enhance bowel motility and enteral fluid secretion Cisapride is a proldnetic agent that promotes propulsive motor activity in the stomach and in small and large intestines. It is used in motility disorders. Its mechanism of action is unclear, but stimulation of 5HT4 receptors may be important... 

Cisapride is a selective cholinomimetic agent with no antidopaminergic activity. It increases acetylcholine release from the myenteric neurons. It has the same indications as metoclopramide but is also useful for dysmotility problems of the lower GI tract. In many countries it has been either withdrawn or has had its indications limited due to reports about long QT syndrome due to cisapride. 

HT4 CNS and myenteric neurons, smooth muscle Gs, t cAMP 5-Methoxytryptamine, renzapride, metoclopramide ... 

Storr M, Hahn A, Gaffal E et al (2002) Effects of endomorphin-1 and -2 on on mu-opioid receptors in myenteric neurons and in the peristaltic reflex in rat small intestine. Clin Exp Pharmacol Physiol 29 428-34... 

In addition to in vitro cell models, opioid agonists could induce the rapid endocytosis of the receptor in organo cultures or primary neuronal cultures, and also neurons in vivo. Treatment of longitudinal muscle-myenteric plexus preparation or the primary hippocampal neuron cultures with DAMGO resulted in internalization of the mu opioid receptor [146,147]. Similar observation was obtained with fluorescently labeled opioid peptides Fluo-dermorphin and Fluo-deltorphin [148]. Within 15 min of an intra-peritoneal injection of etorphine, mu opioid receptor immunoreactivity was observed in the endosomal structures of the myenteric neurons of guinea pig ileum [149]. Again, rapid clustering of a spliced variant of mu opioid receptor MOR-1C was observed in the lateral septum of the mouse after intracere-... 

Subsequent to the molecular cloning and cDNA sequence analysis of the delta opioid receptor, antireceptor antibodies were raised against synthetic peptides based on the deduced amino acid sequence of this receptor. To date, there have been a limited number of studies using antibodies directed toward the amino terminus of the cloned murine receptor to assess the distribution of delta opioid receptorlike immunoreactivity in the gastrointestinal tract, and these have been confined so far to the porcine small intestine. They have shown the presence of delta opioid receptor-immuno-reactive neurons and fibers in both the myenteric and submucosal plexuses and as well as in myenteric neurons maintained in primary culture [22, 23]. Receptor-like immunoreactivity in neuronal cell bodies appears to be localized in the cytoplasm and is likely to be trafficked to nerve terminals. These neurons are coimmunoreactive for the acetylcholine-synthesizing... 

Paraneoplastic autonomic neuropathy is primarily seen with SCLC [103]. Lymphoma, non-small cell lung cancer, and ovarian cancer are also associated with autonomic disturbances [104]. Autonomic dysfunction affects 23-30% of Hu antibody positive patients [36, 98] and is the predominant symptom at presentation in up to 9% of the patients [90]. The onset of symptoms is usually subacute. A prominent clinical manifestation in patients with paraneoplastic autonomic neuropathy is gastrointestinal dysmotility and intestinal pseudo-obstruction, which can occur as part of the PEM/SN syndrome or as the sole symptom of Hu antibody related PNS. Ortostatic hypotension and erectile dysfunction are other common features [37, 105, 106], Autonomic neuropathy is also commonly associated with the CRMP-5 antibody and have been detected in more than 30% of CRMP-5 antibody positive patients [30], Inflammation in autonomic ganglia and infiltration of B and T cells have been demonstrated at autopsy [107], and Hu antibodies have been shown to induce neuronal apoptosis in cultured myenteric neurons [105],... 

GEA3162 was used as a NO donor in order to characterize the action of NO on rat myenteric neurons. It is suggested that NO stimulates the voltage-dependent Ca2+ channels in rat myenteric neurons [74],... 

Met-Enkephalin (MENK) 5 Myenteric neurons (AS and C fibers) Suppresses nociception (5)( /r,) Substance Pantagonism (8)( ) Depresses medullarespiratory center ()u,2) Suppressionof GI motility (/A2) Stimulation of sphinctertone pf)... 

Lopez-Redondo F, Lees GM, Pertwee RG (1997) Effects of cannabinoid receptor ligands on electrophysiological properties of myenteric neurones of the guinea-pig ileum. Br J Pharmacol 122 330-334... 

Kulkarni-Narla A, Brown DR (2001) Opioid, cannabinoid and vaniUoid receptor localization on porcine cultured myenteric neurons. Neurosci Lett 308 153-156... 

Saffrey, M. ]., Hassall, C. ]., Hoyle, C. H., Belai, A., Moss, ]., Schmidt, H. H., Forstermann, U., Murad, F., and Burnstock, G. (1992). Colocalization of nitric oxide synthase and NADPH-diaphorase in cultured myenteric neurons. Neuroreport 3, 333-336. 

Constriction of guinea pig ileum, an action likely to be mediated by an increase of acetylcholine release from myenteric neurones (Mang et al., 2001). 

Inhibition of evoked fast excitatory synaptic potentials of myenteric neurons by CB, agonists. 

Afilimotility drugs are widely used to provide symptomatic relief in mild lu moderate form.s of acute diarrhoea. Opioids such as morp/iiiw. diphetuixyhfe and (We//ie activate p -receptors on myenteric neurones and cause hyperpotari/alion by increasing their potassium conductance. This inhibits acetylcholine release from the myenteric plexus and reduces bowel motility. Loperamide is the most appropriate opioid for local elYects on the gut because it docs not easily penetrate to the brain. Hence, it has few central actions and is unlikely to cause dependence. 

No significant damage of myenteric neurons in the colon of rats or mice was observed after animals were given purgative doses of sennosides in drinking water for 4 or 5 months (Kiernan and Heinicke 1989). 

Cytosolic Liver kidney (cortical proximal tubule) intestine myenteric neu-ronsi ileal and colonic muscles CNS not in astrocytes (selective neurons in neocortex, and midbrain), brainstem, diencephalon, cerebellar molecular and granular layer eye Fibroblasts Cytosolic Liver kidney (cortical proximal tubule) intestine, myenteric neurons, ileal and colonic muscles CNS cerebrum ubiquitous, cerebellum (not in cerebellar white matter) eye Red cells, fibroblasts Arginase 1 cytosol (liver)... 

Vogalis, F. Hillsley, K. Smith, T. Recording ionic events from cultured, Dil-labehed myenteric neurons in the guinea-pig proximal colon. J. Neurosci Methods 2000, 96, 25-34. 

---