Pharmacological identification of the α-adrenergic receptor type which inhibits the β-adrenergic activated adenylate cyclase system in cultured astrocytes
✍ Scribed by William J. Northam; Cynthia A. Bedoy; Philip L. Mobley
- Book ID
- 102224794
- Publisher
- John Wiley and Sons
- Year
- 1989
- Tongue
- English
- Weight
- 484 KB
- Volume
- 2
- Category
- Article
- ISSN
- 0894-1491
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✦ Synopsis
The adrenergic agonist norepinephrine can exert its influence on cell function by activating both a-and 0-adrenergic receptors. In astrocytes, the a-adrenergic receptor activity of norepinephrine is known to inhibit the cyclic AMP response elicited by its action at p-adrenergic receptors. Pharmacological studies were conducted to identify the subtype of a-adrenergic receptor which mediates this inhibitory action. The azadrenergic antagonist yohimbine potentiated the cyclic AMP response elicited by norepinephrine, whereas the al-adrenergic antagonist prazosin did not affect the response. The az- adrenergic agonist clonidine inhibited the cyclic AMP response elicited by the p-adrenergic agonist isoproterenol and this inhibition could be blocked by yohimbine but not by prazosin. In contrast, the al-adrenergic agonist phenylephrine did not inhibit the cyclic AMP response to isoproterenol. These studies indicate that the inhibitory action of norepinephrine is mediated by its action at aa-adrenergic receptors.