Document Detail


Synchronization of enteric neuronal firing during the murine colonic MMC.
MedLine Citation:
PMID:  15731189     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
DiI (1,1'didodecyl-3,3,3',3'-tetramethylindocarbecyanine perchlorate) retrograde labelling and intracellular electrophysiological techniques were used to investigate the mechanisms underlying the generation of spontaneously occurring colonic migrating myoelectric complexes (colonic MMCs) in mice. In isolated, intact, whole colonic preparations, simultaneous intracellular electrical recordings were made from pairs of circular muscle (CM) cells during colonic MMC activity in the presence of nifedipine (1-2 microm). During the intervals between colonic MMCs, spontaneous inhibitory junction potentials (IJPs) were always present. The amplitudes of spontaneous IJPs were highly variable (range 1-20 mV) and occurred asynchronously in the two CM cells, when separated by 1 mm in the longitudinal axis. Colonic MMCs occurred every 151 +/- 7 s in the CM and consisted of a repetitive discharge of cholinergic rapid oscillations in membrane potential (range: 1-20 mV) that were superimposed on a slow membrane depolarization (mean amplitude: 9.6 +/- 0.5 mV; half-duration: 25.9 +/- 0.7 s). During the rising (depolarizing) phase of each colonic MMC, cholinergic rapid oscillations occurred simultaneously in both CM cells, even when the two electrodes were separated by up to 15 mm along the longitudinal axis of the colon. Smaller amplitude oscillations (< 5 mV) showed poor temporal correlation between two CM cells, even at short electrode separation distances (i.e. < 1 mm in the longitudinal axis). When the two electrodes were separated by 20 mm, all cholinergic rapid oscillations and IJPs in the CM (regardless of amplitude) were rarely, if ever, coordinated in time during the colonic MMC. Cholinergic rapid oscillations were blocked by atropine (1 microm) or tetrodotoxin (1 microm). Slow waves were never recorded from any CM cells. DiI labelling showed that the maximum projection length of CM motor neurones and interneurones along the bowel was 2.8 mm and 13 mm, respectively. When recordings were made adjacent to either oral or anal cut ends of the colon, the inhibitory or excitatory phases of the colonic MMC were absent, respectively. In summary, during the colonic MMC, cholinergic rapid oscillations of similar amplitudes occur simultaneously in two CM cells separated by large distances (up to 15 mm). As this distance was found to be far greater than the projection length of any single CM motor neurone, we suggest that the generation of each discrete cholinergic rapid oscillation represents a discreet cholinergic excitatory junction potential (EJP) that involves the synaptic activation of many cholinergic motor neurones simultaneously, by synchronous firing in many myenteric interneurones. Our data also suggest that ascending excitatory and descending inhibitory nerve pathways interact and reinforce each other.
Authors:
Nick J Spencer; Grant W Hennig; Eamonn Dickson; Terence K Smith
Related Documents :
4036529 - Eeg patterns suggestive of shifted levels of excitation effected by hathayogic exercises.
9187589 - Adverse effects of interrupting precordial compression during cardiopulmonary resuscita...
24501549 - Effect of different rest intervals on the exercise volume completed during squat bouts.
17675619 - Multiple-electrode radiofrequency ablation: comparison with a conventional cluster elec...
1708189 - The role of histamine release in shock.
24780769 - Physical exercise training and neurovascular unit in ischemic stroke.
6604479 - Left ventricular performance after coronary artery bypass surgery. prediction of functi...
6822099 - Sensitive indices of improvement in a pulmonary rehabilitation program.
265309 - The effect of partial dentures and chlorhexidine gluconate gel on plaque accumulation i...
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, P.H.S.     Date:  2005-02-24
Journal Detail:
Title:  The Journal of physiology     Volume:  564     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2005 May 
Date Detail:
Created Date:  2005-05-16     Completed Date:  2005-08-11     Revised Date:  2013-06-09    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  829-47     Citation Subset:  IM    
Affiliation:
Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Action Potentials / physiology*
Animals
Biological Clocks / physiology*
Cells, Cultured
Colon / physiology*
Female
Male
Mice
Mice, Inbred C57BL
Motor Neurons / physiology*
Myocytes, Smooth Muscle / physiology*
Synaptic Transmission / physiology*
Grant Support
ID/Acronym/Agency:
R01 DK 45713/DK/NIDDK NIH HHS
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Regulation of activity-dependent dendritic vasopressin release from rat supraoptic neurones.
Next Document:  Ca2+-activated myosin-ATPases, creatine and adenylate kinases regulate mitochondrial function accord...