Characterization of beta-adrenergic receptors of freshly isolated astrocytes and neurons from rat brain.
The binding and characteristics of rat brain beta-adrenergic receptors (beta-AR) isolated from astrocytes and neurons were investigated. Equilibrium binding experiments demonstrated that beta-AR were more concentrated on astrocytes than on neurons isolated from forebrain, cerebral cortex and cerebellum. Inhibition experiments revealed that beta 1-AR and beta 2-AR were present in the two cell types. Isoproterenol revealed two interchangeable states of high and low affinity binding to both beta 1- and beta 2-AR in neurons. The high affinity binding sites were sensitive to guanylylimidodiphosphate (GppNHp). Similar results were found with other beta-AR agonists but not with salbutamol and salmeterol which recognized both affinity states of the neuronal beta 2-AR but only the low affinity state of beta 1-AR. In astrocytes only the low affinity state of beta-AR was observed.
Morin
D
D
Départment de Pharmacologie, Faculté de Médecine de Paris XII, Créteil, France.
Sapena
R
R
Zini
R
R
Onteniente
B
B
Tillement
J P
JP
D000318:Adrenergic beta-Agonists / Q000378:metabolism; D000319:Adrenergic beta-Antagonists / Q000378:metabolism; D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001667:Binding, Competitive; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism; D007093:Imidazoles / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D009474:Neurons / Q000378:metabolism*; D011412:Propanolamines / Q000378:metabolism; D016548:Prosencephalon / Q000166:cytology / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000032:analysis / Q000378:metabolism*
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D007093:Imidazoles; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; C026777:ICI 118551; C049763:CGP 20712A; C033394:CGP 12177