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Renal imidazoline preferring sites and solute excretion in the rat
Author(s) -
Allan D.R.,
Penner S.B.,
Smyth D.D.
Publication year - 1993
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1993.tb13480.x
Subject(s) - moxonidine , idazoxan , imidazoline receptor , rauwolscine , chemistry , endocrinology , medicine , stimulation , alpha (finance) , antagonist , kidney , excretion , agonist , prazosin , pharmacology , receptor , biology , biochemistry , construct validity , nursing , patient satisfaction
1 Moxonidine has been found to have an approximately 600 fold greater affinity for I 1 imidazoline preferring sites as compared to α 2 ‐adrenoceptors in the rat kidney. The effects of an intrarenal infusion of moxonidine in an anaesthetized rat preparation were investigated and contrasted with the effects previously reported for α 2 ‐adrenoceptor stimulation. 2 An intrarenal infusion of moxonidine (1, 3 and 10 nmol kg −1 min −1 ) produced an increase in urine flow rate and sodium excretion. Moxonidine increased urine volume through an increase in osmolar clearance rather than an increase in free water clearance as previously reported for α 2 ‐adrenoceptor stimulation. 3 The effects of moxonidine also appeared to be unique from the effects of α 2 ‐adrenoceptor stimulation. An imidazoline preferring site specific blocking dose of idazoxan (0.3 mg kg −1 ), but not an α 2 ‐adrenoceptor specific blocking dose of rauwolscine (0.3 mg kg −1 ) attenuated the renal effects of moxonidine (3 nmol kg −1 min −1 ). Moreover, unlike α 2 ‐adrenoceptor agonists, the effects of moxonidine were not altered by prior treatment with a V 2 vasopressin receptor antagonist. 4 These results indicate differences between stimulation of α 2 ‐adrenoceptors and I 1 imidazoline preferring sites in the rat kidney and suggest a direct physiological function of renal imidazoline preferring sites.