title: Enhanced inhibitory effect of alpha 2-adrenoceptor stimulation on the formation of cAMP in glomeruli of spontaneously hypertensive rats.
abstract: Renal alpha 2-adrenoceptors are known to be increased in spontaneously hypertensive rats (SHR) compared with Wistar-Kyoto rats (WKY). To investigate whether this difference affects the second messenger system, we examined the effect of alpha 2-adrenoceptor stimulation on the formation of cAMP in microdissected glomeruli and proximal convoluted tubules obtained from the kidneys of SHR and WKY. The formation of glomerular cAMP, which was stimulated by parathyroid hormone (PTH), was inhibited by alpha 2-adrenoceptor stimulation. In contrast, the inhibitory effect of alpha 2-adrenoceptor stimulation on PTH-induced cAMP formation in proximal convoluted tubules was not significantly different between SHR and WKY. These results confirm the inhibitory action of alpha 2-adrenoceptors on the formation of cAMP in glomeruli and proximal tubules and suggest that the greater inhibitory effect on glomerular cAMP formation in SHR may reflect an increase in alpha 2-adrenoceptor density in SHR kidneys.
authors.affiliation: Second Department of Internal Medicine, Yokohama City University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: S
authors.initials: S
authors.lastname: Umemura
authors.forename: N
authors.initials: N
authors.lastname: Hirawa
authors.forename: Y
authors.initials: Y
authors.lastname: Toya
authors.forename: K
authors.initials: K
authors.lastname: Minamisawa
authors.forename: T
authors.initials: T
authors.lastname: Iwamoto
authors.forename: M
authors.initials: M
authors.lastname: Ishii
mesh_terms: D000818:Animals; D000242:Cyclic AMP / Q000032:analysis / Q000378:metabolism*; D004837:Epinephrine / Q000494:pharmacology; D005920:Glomerular Mesangium / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D006973:Hypertension / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D008297:Male; D010281:Parathyroid Hormone / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*
chemical_list: D010281:Parathyroid Hormone; D011942:Receptors, Adrenergic, alpha; D000242:Cyclic AMP; D004837:Epinephrine