Document Detail

Effects of temperature and volume on intraperitoneal saline-induced changes in blood pressure, nociception, and neural activity in the rostroventral medulla.
MedLine Citation:
PMID:  12231457     Owner:  NLM     Status:  MEDLINE    
ON and OFF cells of the rostral ventromedial medulla are hypothesized to modulate nociception with ON cells facilitating pain and OFF cells inhibiting pain. The current study analyzed the effects of intraperitoneal saline at different volumes and temperatures on nociception (tail flick reflex), blood pressure, and the activity of ON and OFF cells in lightly anesthetized rats. At large volumes (20 cc/kg), room temperature saline excited 7/11 ON cells and inhibited 10/12 OFF cells for 2-5 min. In contrast, large volumes (20 cc/kg) of body temperature saline (37 degrees C) excited only 1/10 ON cells and inhibited only 3/13 OFF cells, and small volumes (1-2 cc/kg) of room temperature saline excited only 3/10 ON cells and inhibited only 4/11 OFF cells. Tail flick latency increased following saline administration at large volumes with a significant effect of time, but not temperature. The excitation of ON cells and inhibition of OFF cells indicate that cold intraperitoneal saline could be painful and the increase in tail flick latency may indicate a diffuse noxious inhibitory control. It is also possible that the changes in ON and OFF cell activity caused a hyperalgesia that was masked by a simultaneous hypoalgesia that was mediated independent of the ON and OFF cells. Because intraperitoneal saline may produce pain or hyperalgesia, care should be used when saline is used experimentally or clinically.
Cindy L Thurston-Stanfield
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Brain research     Volume:  951     ISSN:  0006-8993     ISO Abbreviation:  Brain Res.     Publication Date:  2002 Sep 
Date Detail:
Created Date:  2002-09-16     Completed Date:  2002-11-26     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0045503     Medline TA:  Brain Res     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  59-68     Citation Subset:  IM    
Department of Biomedical Sciences, University of South Alabama, UCOM 6000, Mobile, AL 36688, USA.
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MeSH Terms
Action Potentials / drug effects,  physiology
Afferent Pathways / drug effects*,  physiology
Blood Pressure / drug effects,  physiology
Dose-Response Relationship, Drug
Medulla Oblongata / drug effects*,  physiology
Neural Inhibition / drug effects,  physiology
Neurons / drug effects*,  physiology
Nociceptors / drug effects*,  physiology
Pain / chemically induced*,  physiopathology
Peritoneum / drug effects*,  innervation,  physiology
Raphe Nuclei / drug effects,  physiology
Rats, Sprague-Dawley
Reaction Time / drug effects,  physiology
Sodium Chloride / pharmacology*
Grant Support
Reg. No./Substance:
7647-14-5/Sodium Chloride

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