Increased beta 2-adrenoreceptor density in heart, kidney and lung of spontaneously hypertensive rats.
The development of beta-adrenoreceptor density and beta 1- and beta 2-adrenoreceptor distribution has been investigated in heart, kidney and lung of spontaneously hypertensive (SHR) and normotensive (WKY) rats by (-)125I-iodocyanopinolol binding at the age of 5-6, 9-10 and 19-21 weeks. At all ages beta-adrenoreceptor density was similar in hearts of both strains, while it was increased in kidney and lung of SHR compared to WKY. The beta 2-adrenoreceptor density was higher in all three tissues of SHR at all ages investigated. On the other hand, beta 1-adrenoreceptor density was decreased in heart, unchanged in lung and increased in kidney of SHR compared to WKY. Destruction of presynaptic nerve terminals by treatment of WKY with 6-hydroxydopamine produced a 24% loss of cardiac beta 2-adrenoreceptors, whereas the beta 1-adrenoreceptor density remained unchanged, suggesting that at least part of the cardiac beta 2-adrenoreceptor population is localized prejunctionally. It is suggested that beta 2-adrenoreceptors are involved in the development or maintenance of high blood pressure in SHR, possibly by facilitating noradrenaline release.
D000818:Animals; D006892:Hydroxydopamines / Q000494:pharmacology; D006973:Hypertension / Q000378:metabolism*; D066298:In Vitro Techniques; D020120:Iodocyanopindolol; D007668:Kidney / Q000378:metabolism*; D007700:Kinetics; D008168:Lung / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D016627:Oxidopamine; D010869:Pindolol / Q000031:analogs & derivatives; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
D006892:Hydroxydopamines; D011943:Receptors, Adrenergic, beta; D020120:Iodocyanopindolol; D016627:Oxidopamine; D010869:Pindolol; D009638:Norepinephrine