Document Detail


Hypertensive response following stimulation of opiate receptors in the caudal ventrolateral medulla.
MedLine Citation:
PMID:  6145114     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In urethane-anesthetized rats, vasodepressor neuron pools were located bilaterally in and adjacent to the A1 area of the ventrolateral medulla by injecting the neuroexcitatory amino acid, L-glutamate. Ventrolateral vasodepressor areas included the caudalateral part of the nucleus reticularis gigantocellularis, the rostrolateral part of the nucleus reticularis ventralis, and the dorsal nucleus reticularis lateralis. In the ventrolateral vasodepressor areas L-glutamate elicited a transient fall in blood pressure (BP) and heart rate (HR). The opiate agonist (D-ala2-met5)-enkephalinamide (DAME) was used to stimulate opiate receptors in vasodepressor sites, identified with L-glutamate. In these sites, bilateral injections (0.1 microliter/site) of DAME caused a dose-related (2.5-500.0 ng) increase in blood pressure and heart rate, as well as exaggeration of the response to occlusion of the carotid. The effects of DAME on blood pressure were completely abolished by alpha-adrenergic blockade (phentolamine, 2 mg/kg, i.v.) and all effects of DAME were reversed by the administration of naloxone HCl (1 mg/kg, i.v.). Naloxone reversal was accompanied by an unexpected "rebound" hypertension. Saline had no significant effects when injected, or administered intravenously, in the absence or presence of DAME. It was concluded that stimulation of opiate receptors in the ventrolateral vasodepressor areas activated sympathetic outflow. An enkephalinergic system in this area of the brain stem may serve to modulate blood pressure, heart rate and cardiovascular reflexes.
Authors:
R N Willette; S Punnen; A J Krieger; H N Sapru
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Neuropharmacology     Volume:  23     ISSN:  0028-3908     ISO Abbreviation:  Neuropharmacology     Publication Date:  1984 Apr 
Date Detail:
Created Date:  1984-07-10     Completed Date:  1984-07-10     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0236217     Medline TA:  Neuropharmacology     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  401-6     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Pressure / drug effects*
Carotid Arteries / physiology
Enkephalin, Methionine / analogs & derivatives*,  pharmacology
Glutamates / pharmacology
Glutamic Acid
Heart Rate / drug effects*
Male
Medulla Oblongata / physiology*
Naloxone / pharmacology
Rats
Rats, Inbred Strains
Receptors, Opioid / drug effects,  physiology*
Grant Support
ID/Acronym/Agency:
HL 24347/HL/NHLBI NIH HHS; RR05393/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Glutamates; 0/Receptors, Opioid; 465-65-6/Naloxone; 56-86-0/Glutamic Acid; 58569-55-4/Enkephalin, Methionine; 61090-95-7/enkephalinamide-Met, Ala(2)-

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


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