| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Intracellular recordings were obtained from neurones of the guinea-pig submucous plexus. Inhibitory synaptic potentials (i.p.s.p.s) were compared with hyperpolarizations evoked by brief, local applications of noradrenaline and by superfusion with adrenoceptor agonists. Hyperpolarizing potentials elicited by brief applications of noradrenaline were similar to the i.p.s.p. in latency of onset, amplitude, time course, conductance increase, reversal potential and ionic dependence. Both responses were blocked by low concentrations of Ba2+ and quinine. 6-hydroxydopamine selectively and irreversibly abolished the i.p.s.p. and resulted in a complete loss of catecholamine fluorescent nerve fibres in the submucous plexus. The alpha 2-adrenoceptor antagonists, phentolamine, yohimbine and RX781094, reversibly blocked the i.p.s.p. and the noradrenaline hyperpolarization. Prazosin, propranolol, atropine and naloxone had no effect on these responses. Superfusion with noradrenaline and clonidine produced dose-dependent membrane hyperpolarizations. Noradrenaline and clonidine dose-hyperpolarization curves were shifted to the right in a parallel fashion by alpha 2-adrenoceptor antagonists. Determination of the dissociation equilibrium constants for phentolamine, yohimbine and RX781094 showed that the hyperpolarization produced by noradrenaline perfusion is due to alpha 2-adrenoceptor activation. It is concluded that the release of noradrenaline from sympathetic nerves activates post-synaptic alpha 2-adrenoceptors, resulting in the K+ conductance increase which underlies the i.p.s.p. in submucous plexus neurones.
This article has been cited by other articles:
|
|
 |
|
  N. Gao, H.-Z. Hu, S. Liu, C. Gao, Y. Xia, and J. D. Wood Stimulation of adenosine A1 and A2A receptors by AMP in the submucosal plexus of guinea pig small intestine Am J Physiol Gastrointest Liver Physiol, February 1, 2007; 292(2): G492 - G500. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G.-D. Wang, X.-Y. Wang, H.-Z. Hu, X.-C. Fang, S. Liu, N. Gao, Y. Xia, and J. D. Wood Angiotensin receptors and actions in guinea pig enteric nervous system Am J Physiol Gastrointest Liver Physiol, September 1, 2005; 289(3): G614 - G626. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. K. MacNaughton, M. D. Van Sickle, C. M. Keenan, K. Cushing, K. Mackie, and K. A. Sharkey Distribution and function of the cannabinoid-1 receptor in the modulation of ion transport in the guinea pig ileum: relationship to capsaicin-sensitive nerves Am J Physiol Gastrointest Liver Physiol, May 1, 2004; 286(5): G863 - G871. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Liu, H.-Z. Hu, N. Gao, C. Gao, G. Wang, X. Wang, O. C. Peck, G. Kim, X. Gao, Y. Xia, et al. Neuroimmune interactions in guinea pig stomach and small intestine Am J Physiol Gastrointest Liver Physiol, January 1, 2003; 284(1): G154 - G164. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y Xia, H Z Hu, S Liu, C Pothoulakis, and J D Wood Clostridium difficile toxin A excites enteric neurones and suppresses sympathetic neurotransmission in the guinea pig Gut, April 1, 2000; 46(4): 481 - 486. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Q. Yang and S. M. Lanier ACCELERATED COMMUNICATION: Influence of G Protein Type on Agonist Efficacy Mol. Pharmacol., September 1, 1999; 56(3): 651 - 656. [Abstract] [Full Text]
|
|
|
|
|
|
S. Horger, G. Schultheiss, and M. Diener Segment-specific effects of epinephrine on ion transport in the colon of the rat Am J Physiol Gastrointest Liver Physiol, December 1, 1998; 275(6): G1367 - G1376. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
