Atypical synergistic alpha 1- and beta-adrenergic regulation of adenosine 3',5'-monophosphate and guanosine 3',5'-monophosphate in rat pinealocytes.
The adrenergic control of cAMP and 3',5'-cyclic GMP (cGMP) in dispersed adult rat pinealocytes was investigated. Norepinephrine treatment increased cAMP and cGMP content 60- and 400-fold, respectively; both alpha- and beta-adrenoceptors had to be activated for these responses to occur. Beta-Adrenergic stimulation alone produced only about 6- and 2-fold increase in cAMP and cGMP content, respectively. Alpha-Adrenergic stimulation, which alone had no effect on either cyclic nucleotide concentration, markedly amplified the beta-adrenergic stimulation of both cAMP and cGMP. The relative potency of alpha-adrenergic agonists and antagonists indicates the alpha 1-subclass of adrenoceptors is involved. A role of alpha 1-adrenoceptors in the control of pineal cAMP is consistent with published evidence of the presence of alpha 1-adrenoceptors on pinealocytes and their role in the regulation of N-acetyltransferase activity and melatonin production.
Vanecek
J
J
Sugden
D
D
Weller
J
J
Klein
D C
DC
D000818:Animals; D000242:Cyclic AMP / Q000032:analysis*; D006152:Cyclic GMP / Q000032:analysis*; D004305:Dose-Response Relationship, Drug; D005260:Female; D066298:In Vitro Techniques; D009638:Norepinephrine / Q000494:pharmacology; D010870:Pineal Gland / Q000032:analysis* / Q000187:drug effects; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D013565:Sympatholytics / Q000494:pharmacology; D013566:Sympathomimetics / Q000494:pharmacology; D013997:Time Factors
D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D013565:Sympatholytics; D013566:Sympathomimetics; D000242:Cyclic AMP; D006152:Cyclic GMP; D009638:Norepinephrine