Tags

Type your tag names separated by a space and hit enter

Response properties of antral mechanosensitive afferent fibers and effects of ionotropic glutamate receptor antagonists.
Neuroscience. 2004; 125(3):711-23.N

Abstract

The ionotropic glutamate receptors N-methyl-d-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are present peripherally in the primary sensory afferent neurons innervating the viscera. Multiple studies have reported roles of glutamate receptors in gastric functions. However, no study has previously shown the direct influence of ionotropic glutamate receptor antagonist on vagal sensory neurons. The objective of this study was to investigate the effects of NMDA and AMPA receptor antagonists on mechanotransduction properties of vagal afferent fibers innervating the rat stomach. Action potentials were recorded from the hyponodal vagus nerve innervating the antrum of the Long-Evans rats. For antral distension (AD), a small latex balloon was inserted into the stomach and positioned in the antrum. The antral contractions were recorded with solid-state probe inserted into the water-filled balloon. Antral units were identified to isovolumic (0.2-1 ml) or isobaric AD (5-60 mm Hg). NMDA and AMPA receptor antagonists were injected in a cumulative fashion (1-100 micromol/kg, i.v.). After the conclusion of experiment, the abdomen was opened and receptive field was mapped by probing the serosa of the stomach. Thirty-two fibers were identified to AD. The receptive fields of 26 fibers were located in the posterior part of the antrum. All fibers exhibited spontaneous firing (mean: 7.00+/-0.97 impulses/s). Twenty fibers exhibited a rhythmic firing that was in phase with antral contractions, whereas 12 fibers exhibited non-rhythmic spontaneous firing unrelated to spontaneous antral contraction. Both groups of fibers exhibited a linear increase in responses to graded isovolumic or isobaric distensions. NMDA (memantine HCl and dizocilpine (MK-801)) and AMPA/kainate (6-cyano-7-nitroquinoxaline 2,3-dione; CNQX) receptor antagonists dose-dependently attenuated the mechanotransduction properties of these fibers to AD. However, competitive NMDA antagonist dl-2-amino-5 phosphopentanoic acid (AP-5) had no effect. The study documents that glutamate receptor antagonists can attenuate responses of gastric vagal sensory afferent fibers innervating the distal stomach, offering insight to potential pharmacological agents in the treatment of gastric disorders.

Authors+Show Affiliations

Division of Gastroenterology and Hepatology, MaccFund Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA. sengupta@mcw.eduNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

15099685

Citation

Sengupta, J N., et al. "Response Properties of Antral Mechanosensitive Afferent Fibers and Effects of Ionotropic Glutamate Receptor Antagonists." Neuroscience, vol. 125, no. 3, 2004, pp. 711-23.
Sengupta JN, Petersen J, Peles S, et al. Response properties of antral mechanosensitive afferent fibers and effects of ionotropic glutamate receptor antagonists. Neuroscience. 2004;125(3):711-23.
Sengupta, J. N., Petersen, J., Peles, S., & Shaker, R. (2004). Response properties of antral mechanosensitive afferent fibers and effects of ionotropic glutamate receptor antagonists. Neuroscience, 125(3), 711-23.
Sengupta JN, et al. Response Properties of Antral Mechanosensitive Afferent Fibers and Effects of Ionotropic Glutamate Receptor Antagonists. Neuroscience. 2004;125(3):711-23. PubMed PMID: 15099685.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Response properties of antral mechanosensitive afferent fibers and effects of ionotropic glutamate receptor antagonists. AU - Sengupta,J N, AU - Petersen,J, AU - Peles,S, AU - Shaker,R, PY - 2004/02/05/accepted PY - 2004/4/22/pubmed PY - 2004/8/3/medline PY - 2004/4/22/entrez SP - 711 EP - 23 JF - Neuroscience JO - Neuroscience VL - 125 IS - 3 N2 - The ionotropic glutamate receptors N-methyl-d-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are present peripherally in the primary sensory afferent neurons innervating the viscera. Multiple studies have reported roles of glutamate receptors in gastric functions. However, no study has previously shown the direct influence of ionotropic glutamate receptor antagonist on vagal sensory neurons. The objective of this study was to investigate the effects of NMDA and AMPA receptor antagonists on mechanotransduction properties of vagal afferent fibers innervating the rat stomach. Action potentials were recorded from the hyponodal vagus nerve innervating the antrum of the Long-Evans rats. For antral distension (AD), a small latex balloon was inserted into the stomach and positioned in the antrum. The antral contractions were recorded with solid-state probe inserted into the water-filled balloon. Antral units were identified to isovolumic (0.2-1 ml) or isobaric AD (5-60 mm Hg). NMDA and AMPA receptor antagonists were injected in a cumulative fashion (1-100 micromol/kg, i.v.). After the conclusion of experiment, the abdomen was opened and receptive field was mapped by probing the serosa of the stomach. Thirty-two fibers were identified to AD. The receptive fields of 26 fibers were located in the posterior part of the antrum. All fibers exhibited spontaneous firing (mean: 7.00+/-0.97 impulses/s). Twenty fibers exhibited a rhythmic firing that was in phase with antral contractions, whereas 12 fibers exhibited non-rhythmic spontaneous firing unrelated to spontaneous antral contraction. Both groups of fibers exhibited a linear increase in responses to graded isovolumic or isobaric distensions. NMDA (memantine HCl and dizocilpine (MK-801)) and AMPA/kainate (6-cyano-7-nitroquinoxaline 2,3-dione; CNQX) receptor antagonists dose-dependently attenuated the mechanotransduction properties of these fibers to AD. However, competitive NMDA antagonist dl-2-amino-5 phosphopentanoic acid (AP-5) had no effect. The study documents that glutamate receptor antagonists can attenuate responses of gastric vagal sensory afferent fibers innervating the distal stomach, offering insight to potential pharmacological agents in the treatment of gastric disorders. SN - 0306-4522 UR - https://www.unboundmedicine.com/medline/citation/15099685/Response_properties_of_antral_mechanosensitive_afferent_fibers_and_effects_of_ionotropic_glutamate_receptor_antagonists_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0306452204001320 DB - PRIME DP - Unbound Medicine ER -