Role of I(1)-imidazoline receptors and alpha2-adrenoceptors in hemodynamic effects of moxonidine administration into the rostroventrolateral medulla.
Local injection of 4 nmol moxonidine (unilaterally) into the rostroventrolateral medulla of spontaneously hypertensive rats (SHR-SP) decreased mean blood pressure and heart rate by 24+/-3 and 3+/-4%, respectively. Pretreatment with the I1/alpha2-receptor antagonist efaroxan abolished the moxonidine-induced decrease in mean blood pressure, but had no effect on heart rate. Yohimbine blocked hypotension, delayed bradycardia (8 nmol), or completely inhibited the effects of moxonidine (16 nmol). Our results indicate that both I1-imidazoline receptors and alpha2-adrenoceptors of the rostroventrolateral medulla are involved in the realization of moxonidine-induced changes.
Khokhlova
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M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry (Pushchino Branch), Russian Academy of Sciences. khohlova@fibkh.serpukhov.su
Murashev
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Medvedev
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D058669:Adrenergic alpha-2 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001572:Benzofurans / Q000008:administration & dosage; D001794:Blood Pressure / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology*; D054755:Imidazoline Receptors; D008297:Male; D008526:Medulla Oblongata; D051381:Rats; D011918:Rats, Inbred SHR; D018341:Receptors, Adrenergic, alpha-2 / Q000378:metabolism*; D011955:Receptors, Drug / Q000378:metabolism*; D015016:Yohimbine / Q000008:administration & dosage
D058669:Adrenergic alpha-2 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D000959:Antihypertensive Agents; D001572:Benzofurans; D007093:Imidazoles; D054755:Imidazoline Receptors; D018341:Receptors, Adrenergic, alpha-2; D011955:Receptors, Drug; C410887:imidazoline I1 receptors; D015016:Yohimbine; C043482:moxonidine; C062597:efaroxan