title: Alterations in alpha adrenergic receptors in human cerebral arteries after subarachnoid hemorrhage.
abstract: The nature of alpha adrenergic receptors in human cerebral arteries was characterized and alteration of these receptors after subarachnoid hemorrhage (SAH) was examined using a radioligand binding assay. The specific 3H-prazosin binding to human cerebral arteries was saturable and of high affinity (KD = 4.1 nM) with a Bmax of 92 fmol/mg protein. Specific 3H-yohimbine binding to these tissues was also saturable and of high affinity (KD = 23 nM) with a Bmax 250 fmol/mg protein. IC50 values of adrenergic agents for 3H-prazosin binding were as follows: prazosin, 1.2 X 10(-10) M; phentolamine, 1.3 x 10(-6) M; yohimbine, 1.2 x 10(-5); norepinephrine, 4.9 x 10(-4) M; epinephrine greater than 1 x 10(-3) M. IC50 values of adrenergic agents for 3H-yohimbine binding were as follows: phentolamine, 1.7 x 10(-7) M; yohimbine, 4.2 x 10(-7) M; prazosin, 1.9 x 10(-5) M; epinephrine, 4.4 x 10(-5) M; norepinephrine, 7.9 x 10(-4) M. KD and Bmax of 3H-prazosin and 3H-yohimbine binding after SAH were compared with findings in the non-SAH group. KD and Bmax of 3H-prazosin binding of SAH group were 6 +/- 3 nM and 90 +/- 10 fmol/mg protein, respectively (N = 3). KD and Bmax of 3H-yohimbine binding of SAH group were 42 +/- 6 nM and 460 +/- 30 fmol/mg protein, respectively (N = 5). On the other hand, KD and Bmax of 3H-prazosin binding in the non-SAH group were 4 +/- 1 nM and 90 +/- 20 fmol/mg protein, respectively (N = 5), KD and Bmax of 3H-yohimbine binding of non-SAH group were 20 +/- 5 nM and 260 +/- 30 fmol/mg protein, respectively (N = 6).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.forename: T
authors.initials: T
authors.lastname: Tsukahara
authors.forename: T
authors.initials: T
authors.lastname: Taniguchi
authors.forename: M
authors.initials: M
authors.lastname: Fujiwara
authors.forename: H
authors.initials: H
authors.lastname: Handa
authors.forename: M
authors.initials: M
authors.lastname: Nishikawa
mesh_terms: D000368:Aged; D002536:Cerebral Arteries / Q000378:metabolism*; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011224:Prazosin / Q000037:antagonists & inhibitors / Q000378:metabolism; D011942:Receptors, Adrenergic, alpha / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D013345:Subarachnoid Hemorrhage / Q000378:metabolism*; D015016:Yohimbine / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D009638:Norepinephrine; D011224:Prazosin; D004837:Epinephrine; D010646:Phentolamine