Document Detail

Acid-evoked currents in cardiac sensory neurons: A possible mediator of myocardial ischemic sensation.
MedLine Citation:
PMID:  10222339     Owner:  NLM     Status:  MEDLINE    
Sensory neurons that innervate the heart sense ischemia and mediate angina. To use patch-clamp methods to study ion channels on these cells, we fluorescently labeled cardiac sensory neurons (CSNs) in rats so that they could later be identified in dissociated primary culture of either nodose or dorsal root ganglia (DRG). Currents evoked by a variety of different agonists imply the importance of lowered pH (</=7.0) in signaling ischemia. Acidic pH evoked extremely large depolarizing current in almost all cardiac afferent neurons from the DRG (CDRGNs). In contrast, only about half of the unlabeled DRG neurons responded to acid, and their current amplitudes were much less than that in CDRGNs. In all respects tested--kinetics, selectivity, and pharmacology--the acid-evoked current was similar to that of previously described native and cloned acid-sensing ion channels. Cardiac afferents from the nodose ganglia differed from CDRGNs in having smaller acid-evoked currents but clearly larger currents evoked by ATP. Serotonin, acetylcholine, bradykinin, and adenosine elicited currents in fewer CSNs than did ATP or lowered pH, and the currents were relatively small. Capsaicin, an activator of small nociceptive sensory neurons that innervate skin, evoked only small and rare currents in CDRGNs. The extremely large amplitude and prevalent expression of acid-evoked current in CSNs imply a critical role for acidity in sensation associated with myocardial ischemia.
C J Benson; S P Eckert; E W McCleskey
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation research     Volume:  84     ISSN:  0009-7330     ISO Abbreviation:  Circ. Res.     Publication Date:  1999 Apr 
Date Detail:
Created Date:  1999-05-20     Completed Date:  1999-05-20     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0047103     Medline TA:  Circ Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  921-8     Citation Subset:  IM    
Vollum Institute, Division of Cardiology, Oregon Health Sciences University, Portland, Ore. 97201-3098, USA.
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MeSH Terms
Adenosine Triphosphate / pharmacology
Heart / innervation*
Hydrogen-Ion Concentration
Ion Channels / physiology*
Myocardial Ischemia / physiopathology*
Neurons, Afferent / physiology*
Rats, Sprague-Dawley
Serotonin / pharmacology
Grant Support
Reg. No./Substance:
0/Ion Channels; 50-67-9/Serotonin; 56-65-5/Adenosine Triphosphate

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