Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 1 de 1
Filter
Add more filters










Database
Language
Publication year range
1.
Can J Physiol Pharmacol ; 92(8): 645-54, 2014 Aug.
Article in English | MEDLINE | ID: mdl-25065747

ABSTRACT

The aim of this study was to explain the involvement of the central histaminergic system in arachidonic acid (AA)-induced cardiovascular effects in normotensive rats using hemodynamic, immunohistochemistry, and microdialysis studies. Intracerebroventricularly (i.c.v.) administered AA (0.25, 0.5, and 1.0 µmol) induced dose- and time-dependent increases in mean arterial pressure and decreased heart rate in conscious normotensive Sprague-Dawley rats. Central injection of AA (0.5 µmol) also increased posterior hypothalamic extracellular histamine levels and produced strong COX-1 but not COX-2 immunoreactivity in the posterior hypothalamus of rats. Moreover, the cardiovascular effects and COX-1 immunoreactivity in the posterior hypothalamus induced by AA (0.5 µmol; i.c.v.) were almost completely blocked by the H2 receptor antagonist ranitidine (50 and 100 nmol; i.c.v.) and partially blocked by the H1 receptor blocker chlorpheniramine (100 nmol; i.c.v.) and the H3-H4 receptor antagonist thioperamide (50 and 100 nmol; i.c.v.). In conclusion, these results indicate that centrally administered AA induces pressor and bradycardic responses in conscious rats. Moreover, we suggest that AA may activate histaminergic neurons and increase extracellular histamine levels, particularly in the posterior hypothalamus. Acting as a neurotransmitter, histamine is potentially involved in AA-induced cardiovascular effects under normotensive conditions.


Subject(s)
Arachidonic Acid/metabolism , Cardiovascular Physiological Phenomena , Histamine/metabolism , Hypothalamus, Posterior/metabolism , Animals , Arachidonic Acid/pharmacology , Blood Pressure/drug effects , Cardiovascular Physiological Phenomena/drug effects , Chlorpheniramine/pharmacology , Cyclooxygenase 1/metabolism , Cyclooxygenase 2/metabolism , Heart Rate/drug effects , Histamine/pharmacology , Histamine Antagonists/pharmacology , Male , Neurons/drug effects , Neurons/metabolism , Neurotransmitter Agents/pharmacology , Piperidines/pharmacology , Ranitidine/pharmacology , Rats, Sprague-Dawley
SELECTION OF CITATIONS
SEARCH DETAIL
...