Document Detail

Microinjections of 5-HT1A agonists into the dorsal motor vagal nucleus produce a bradycardia in the atenolol-pretreated anaesthetized rat.
MedLine Citation:
PMID:  1797313     Owner:  NLM     Status:  MEDLINE    
1. The effects of microinjections (100 nl) into the dorsal motor vagal nucleus of the 5-HT1A receptor agonists 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and flesinoxan, the 5-HT2 receptor agonist (+-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI), the 5-HT3 receptor agonist phenylbiguanide (PBG), the alpha 2-adrenoceptor agonist clonidine and the excitatory amino acid glutamate on heart rate, blood pressure, tracheal pressure and phrenic nerve activity were investigated in atenolol-pretreated rats anaesthetized with sodium pentobarbitone. 2. Microinjections of glutamate (2.5 nmol) caused decreases in blood pressure, heart rate and phrenic nerve activity. In contrast, microinjections of 5-HT (1.2 nmol), 8-OH-DPAT (1.2 nmol) and flesinoxan (1.3 nmol) all caused a bradycardia but had no effect on blood pressure. In addition, 8-OH-DPAT and flesinoxan caused an increase in phrenic nerve activity. 3. Microinjections of DOI, PBG and clonidine had no significant effect on any of the variables recorded. None of the drugs used had any significant effect on tracheal pressure. 4. These results support the hypothesis that activation of 5-HT1A receptors causes excitation of cardiac vagal motoneurones and suggest that these receptors are also important in the control of central respiratory drive.
S C Sporton; S L Shepheard; D Jordan; A G Ramage
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  British journal of pharmacology     Volume:  104     ISSN:  0007-1188     ISO Abbreviation:  Br. J. Pharmacol.     Publication Date:  1991 Oct 
Date Detail:
Created Date:  1992-04-13     Completed Date:  1992-04-13     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  7502536     Medline TA:  Br J Pharmacol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  466-70     Citation Subset:  IM    
Academic Department of Pharmacology, Royal Free Hospital School of Medicine, Hampstead, London.
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MeSH Terms
Heart Rate / drug effects
Medulla Oblongata / drug effects*
Phrenic Nerve / drug effects*
Rats, Inbred Strains
Receptors, Serotonin / drug effects*
Serotonin / pharmacology
Grant Support
//Wellcome Trust
Reg. No./Substance:
0/Receptors, Serotonin; 29122-68-7/Atenolol; 50-67-9/Serotonin; 76-74-4/Pentobarbital

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