REGULATION OF CYCLIC-AMP PRODUCTION IN ADULT HUMAN CILIARY PROCESSES

Cyclic AMP production in intact ciliary processes from elderly human d onors is subject to stimulatory and inhibitory control by various agen ts. Stimulation of cAMP production is observed with forskolin, vasoact ive intestinal peptide, or the beta-adrenergic agonist isoproterenol. Inhibition of forskolin-stimulated cAMP production is observed with en dothelin-2 or PAC. The inhibitory effect of PAC is blocked by the spec ific alpha(2)-adrenergic antagonist, yohimbine. Endothelin-2 has no ef fect on basal cAMP production. These data document the positive and ne gative regulation of cAMP responses in adult human ciliary processes a nd support the idea that cAMP is a key intermediate in the regulation of aqueous humor formation.