Basic-alimentary tractMetabotropic glutamate receptors inhibit mechanosensitivity in vagal sensory neurons
Section snippets
RT-PCR analysis
Total RNA was isolated from nodose ganglia and brain from rat, dog, ferret, and human, using Trizol (Life Technologies, Inc.). One to 2.5 μg total RNA was reverse transcribed at 42°C for 50 minutes in the presence of 0.5 μg/μL oligo (dT)12, 13, 14, 15, 16, 17, 18 primer, 10 × RT buffer (200 mmol/L Tris-HCl, pH 8.4, 500 mmol/L KCl, 25 mmol/L MgCl2), 10 mmol/L DTT, 10 mmol/L of each dNTP, 40 U Recombinant Ribonuclease Inhibitor and 50 U Reverse Transcriptase (SuperScript II, from Life
Results
We compared mGluR expression in vagal afferent cell bodies in the nodose ganglia of humans, dogs, ferrets, and rats. All 8 mGluR transcripts were detected in rat and dog nodose ganglion and brain using primers designed to detect human and rat sequences (Figure 1A and 1B), and identity of products was confirmed by sequencing. In human and in ferret, all except mGluR 3 and 6 could be detected in nodose, and mGluR6 was not evident in nodose or brain specimens.
Retrograde tracing from the ferret
Discussion
Interest is intensifying in pharmacologic approaches to reducing input from afferent neurons to the brain and spinal cord, in particular from groups of afferent neurons that may contribute to diseased states or to pain. Vagal afferents provide input to pathways in the brain that are involved in triggering of behavioral responses,22, 23 reflexes controlling digestive function,24 and, importantly, motor patterns that lead to gastroesophageal reflux.25, 26 Therefore, any means of reducing this
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2020, Progress in Molecular Biology and Translational ScienceCitation Excerpt :Intraganglionic laminar endings terminate on the basal lamina surrounding myenteric ganglia and are sensitive to distension and muscle contraction. The tension-sensitive afferents, which are principally sensitive to physiological distension, are activated by normal peristaltic activity.239,240 Vagal mucosal afferents have been detected in the stomach mucosa and in the villus and crypts of the small intestine mucosa, and serve to detect chemical stimuli, such as gastric acid, to regulate satiety, to allow food particle passage into the duodenum and to sense local hormones secreted by the mucosa, luminal molecules such as bacterial metabolites, or neuromodulators/neurotransmitters, to start vagal reflexes.205
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2016, NeuropharmacologyCitation Excerpt :mGlu receptors may also participate to transmit vagal afferent signals from the upper part of the gastrointestinal tract to the CNS. Application of standard RT-PCR and retrograde fluorescent immunolabelling techniques showed the presence of all mGluRs mRNAs and protein in the NVG and NTS of several species including rat, human, dog, rodent and ferret (Hoang and Lay, 2001; Page et al., 2005; Slattery et al., 2006). In the rat and human esophagus, mGlu1 and mGlu4 receptors are also located at a postjunctional level in the mucosal and smooth muscle layer (Akiba et al., 2009; Chang et al., 2005a).
Supported by National Health and Medical Research Council grant 104814, AstraZeneca, and the University of Adelaide (J.R.C. and C.M.M).