title: Atrial natriuretic peptide (ANP), guanylate cyclase, and intraocular pressure in the rabbit eye.
abstract: Synthetic rat atrial natriuretic peptide (ANP) was examined for effects on guanylate-and on adenylate cyclase activity in ciliary process homogenates and for effects on intraocular pressure in the albino rabbit eye. Ciliary process guanylate cyclase was associated predominantly with the particulate fraction and was partially activated by ANP (EC50, approximately 1 nM) relative to a maximal dose of Na Nitroprusside (2 uM), whereas particulate adenylate cyclase (basal as well as forskolin-stimulated activity) showed no responses to ANP at doses up to 0.3 uM. Particulate cAMP phosphodiesterase activity was stimulated by low doses of cGMP (1-5 uM) in ciliary processes. Thus, ANP, acting via guanylate cyclase, has the potential to regulate phosphodiesterase activity and indirectly decrease cAMP levels in membranes derived from ciliary processes. Intravitreous injection of ANP (2-4 ug/eye) caused a small decrease (1-1.5 mm Hg) in intraocular pressure measured 16-24 hours after injection but the pressure had returned to normal by 40 hours. The findings demonstrate regulation of biochemical and pharmacological responses by ANP in the albino rabbit eye suggesting that this peptide may play a physiological role in secretory functions of ciliary processes.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D002924:Ciliary Body / Q000201:enzymology*; D005576:Colforsin / Q000494:pharmacology; D006152:Cyclic GMP / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000378:metabolism*; D007267:Injections; D007429:Intraocular Pressure; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011817:Rabbits; D014822:Vitreous Body
chemical_list: D005576:Colforsin; D004533:Egtazic Acid; D009320:Atrial Natriuretic Factor; D010727:Phosphoric Diester Hydrolases; D000262:Adenylyl Cyclases; D006162:Guanylate Cyclase; D006152:Cyclic GMP