HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 545/3/1007    most recent 2002.021337v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sahibzada, N. Articles by Gillis, R. A. Search for Related Content PubMed PubMed Citation Articles by Sahibzada, N. Articles by Gillis, R. A.

Nicotinic ACh receptor subtypes on gastrointestinally projecting neurones in the dorsal motor vagal nucleus of the rat

Niaz Sahibzada *†, Manuel Ferreira Jr *, Bernice Williams †, Adam Wasserman *, Stefano Vicini ‡ and Richard A. Gillis *

To determine the predominant nicotinic ACh receptor (nAChR) located on neurones in the dorsal motor nucleus of the vagus (DMV) that project to the gastrointestinal tract, we used the rat brainstem slice preparation and whole-cell recordings of DMV neurones identified by retrograde DiI tracing to pharmacologically characterize nAChRs. Pressure ejection of acetylcholine (ACh, 250 µM for 200 ms) from a patch pipette placed ~10-20 µm from the surface of the recorded cell produced an inward current in most DMV neurones sampled. The average currents for neurones projecting to the fundus, antrum and caecum were 149 ± 38 (n = 25), 115 ± 18 (n = 29) and 117 ± 23 pA (n = 6), respectively. Blockade of the 7 subtype of nAChR with either -bungarotoxin (-BGT) or methyllycaconitine (MLA) counteracted 60-75 % of the ACh-evoked current in DMV neurones projecting to the fundus, antrum and caecum. In neurones projecting to the fundus and the antrum, currents resistant to -BGT were significantly blocked by dihydro--erythroidine (10-20 nM), an antagonist of the 42 subtype of nAChR. In neurones projecting to the caecum, currents resistant to -BGT were significantly depressed by a low concentration of mecamylamine (1 µM). Cytisine (100 µM), an agonist of nAChRs that contain the 7 or the 4 subunit, evoked significant currents in caecum-projecting neurones that were previously exposed to -BGT. In contrast, cytisine had no effect on DMV neurones previously exposed to -BGT that project to the fundus or antrum. Our data indicate that the prevailing nAChR subtype in DMV neurones projecting to the GI tract is the 7 subtype. In addition, we obtained evidence for the co-expression of the 42 nAChR subtype on DMV neurones projecting to the fundus and antrum, and the 34 nAChR subtype on DMV neurones projecting to the caecum.

This article has been cited by other articles:

				K. N. Browning and R. A. Travagli Functional Organization of Presynaptic Metabotropic Glutamate Receptors in Vagal Brainstem Circuits J. Neurosci., August 22, 2007; 27(34): 8979 - 8988. [Abstract] [Full Text] [PDF]

				D. W. Adelson, H. P. Kosoyan, Y. Wang, J. Z. Steinberg, and Y. Tache Gastric Vagal Efferent Inhibition Evoked by Intravenous CRF Is Unrelated to Simultaneously Recorded Vagal Afferent Activity in Urethane-Anesthetized Rats J Neurophysiol, April 1, 2007; 97(4): 3004 - 3014. [Abstract] [Full Text] [PDF]