Premium
Agonist‐Induced Regulation of Adrenoceptor Subtypes in Cerebral Cortical Slices
Author(s) -
Nukina Itaru,
LaBella Frank S.
Publication year - 1987
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1987.tb02877.x
Subject(s) - rauwolscine , endocrinology , medicine , dihydroalprenolol , agonist , adrenergic receptor , chemistry , beta (programming language) , beta 1 adrenergic receptor , alpha (finance) , antagonist , adrenergic , metoprolol , cerebral cortex , receptor , biology , prazosin , partial agonist , construct validity , nursing , computer science , patient satisfaction , programming language
Cerebral cortical slices from rat brain were incubated at 37°C for 2 h in the presence of isoproterenol, noradrenaline, or adrenaline, and binding affinities and densities of adrenoceptor subtypes were subsequently examined in homogenized tissue. The density of α 2 ‐and total β‐adre‐noceptors was estimated using the radioligands [ 3 H]rauwolscine and [ 3 H]dihydroalprenolol (DHA), respectively. The percentages of β 1 ‐and β 2 ‐adrenoceptors were denned by inhibiting the binding of [ 3 H]DHA with the β 1 ‐selective antagonist metoprolol. Exposure of slices to noradrenaline and adrenaline significantly decreased the maximal number of binding sites (B max ) of α 2 ‐adrenoceptors (48 and 37% respectively) without significantly affecting affinity; isoproterenol had no effect. Exposure to isoproterenol, noradrena line, and adrenaline significantly decreased the B max of β‐adrenoceptors (by 60, 34, and 24%, respectively) but did not affect the affinity. Isoproterenol and adrenaline significantly decreased the density of β 1 ‐adrenoceptors by 75 and 24% and β 2 ‐radrenoceptors by 23 and 28%, respectively. Noradrenaline significantly decreased the density of β 1 ‐adreno‐ceptors by 42% without affecting the number of β 2 ‐adreno‐ceptors. These findings indicate that subtypes of adrenoceptors in rat cerebral cortex are differentially regulated by adrenergic agonists.