1. Peripheral mechanisms involved in the pressor and bradycardic effects of centrally administered arachidonic acid
- Author
-
Cenk Aydin, Murat Yalcin, Uludağ Üniversitesi/Veteriner Fakültesi/Fizyoloji Anabilim Dalı., Aydın, Cenk, Yalçın, Murat, and AAG-6956-2021
- Subjects
Male ,Vasopressin ,Blood pressure regulation ,Biochemistry & molecular biology ,Rats, sprague-dawley ,Vasopressin secretion ,Clinical Biochemistry ,Plasma renin activity ,Thromboxane a2 analog ,chemistry.chemical_compound ,Norepinephrine ,Histamine H4 Receptors ,Thioperamide ,Chlorpheniramine Maleate ,Sasopressin blood level ,Heart Rate ,Renin ,Protein blood level ,Endocrinology & metabolism ,Priority journal ,Cardiovascular effect ,Noradrenalin blood level ,Receptor antagonist ,Normotensive conscious rats ,Adrenalin blood level ,Mean arterial pressure ,Cardiovascular system ,Vasopressin receptor antagonist ,Arachidonic acid ,Drug effectD ,Blood pressure ,Hemorrhaged hypotensive rats ,Arginine vasopressin ,Injections, intraventricular ,Sympatho-adrenomedullary outflow ,Blood-pressure ,medicine.drug ,Adrenergic alpha-antagonists ,Angiotensin II type 1 receptor blockers ,medicine.medical_specialty ,Cell biology ,Epinephrine ,medicine.drug_class ,Vasopressins ,Central cholinergic system ,Activation ,Article ,Hormone action ,Internal medicine ,medicine ,Prazosin ,Bradycardia ,Animals ,Injected u-46619 ,Clinical evaluation ,Animal experiment ,Antagonist ,Hormone antagonists ,Melittin ,Nonhuman ,[Beta mercapto beta,beta cyclopentamethylenepropionyl 2 (o methyltyrosine) 8 arginine] vasopressin ,Rats ,Endocrinology ,chemistry ,Rat ,Adrenalin ,Saralasin ,Hormone blood level ,Controlled study - Abstract
In the current study, we aimed to determine the cardiovascular effects of arachidonic acid and peripheral mechanisms mediated these effects in normotensive conscious rats. Studies were performed in male Sprague Dawley rats. Arachidonic acid was injected intracerebroventricularly (i.c.v.) at the doses of 75, 150 or 300 microg and it caused dose- and time-dependent increase in mean arterial pressure and decrease in heart rate in normal conditions. Maximal effects were observed 10 min after 150 and 300 microg dose of arachidonic acid and lasted within 30 min. In order to evaluate the role of main peripheral hormonal mechanisms in those cardiovascular effects, plasma adrenaline, noradrenaline, vasopressin levels and renin activity were measured after arachidonic acid (150 microg; i.c.v.) injection. Centrally injected arachidonic acid increased plasma levels of all these hormones and renin activity. Intravenous pretreatments with prazosin (0.5 mg/kg), an alpha1 adrenoceptor antagonist, [beta-mercapto-beta,beta-cyclopentamethylenepropionyl1, O-Me-Tyr2-Arg8]-vasopressin (10 microg/kg), a vasopressin V1 receptor antagonist, or saralasin (250 microg/kg), an angiotensin II receptor antagonist, partially blocked the pressor response to arachidonic acid (150 microg; i.c.v.) while combined administration of these three antagonists completely abolished the effect. Moreover, both individual and combined antagonist pretreatments fully blocked the bradycardic effect of arachidonic acid. In conclusion, our findings show that centrally administered arachidonic acid increases mean arterial pressure and decreases heart rate in normotensive conscious rats and the increases in plasma adrenaline, noradrenaline, vasopressin levels and renin activity appear to mediate the cardiovascular effects of the drug.
- Published
- 2008