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Timolol inhibits adenylate cyclase activity in the iris‐ciliary body and trabecular meshwork of the eye and blocks activation of the enzyme by salbutamol
Author(s) -
Phylactos Andreas C.
Publication year - 1986
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.1986.tb00677.x
Subject(s) - timolol , trabecular meshwork , ciliary body , cyclase , iris (biosensor) , chemistry , adenylate kinase , endocrinology , intraocular pressure , medicine , salbutamol , ciliary muscle , enzyme , glaucoma , ciliary processes , pharmacology , ophthalmology , biology , biochemistry , computer security , accommodation , neuroscience , asthma , computer science , biometrics
The enzymatic activity of adenylate cyclase in homogenates and membrane‐rich fractions prepared from rabbit iris‐ciliary bodies and bovine trabecular meshwork was found to be inhibited by timolol. Treatment of iris‐ciliary body homogenates with Triton X‐305 resulted in abolition of the inhibitory effect of the drug on the activity of the enzyme. The stimulatory effect of salbutamol on the enzyme was also susceptible to blockade by timolol. It is suggested that the hypotensive action of timolol on intraocular pressure results from structural and functional changes induced on the plasma membranes of the iris‐ciliary body and trabecular meshwork by the thiadiazole group of the molecule, and, also, from the occupation of the adrenergic receptors of the iris‐ciliary body by the tert‐butylamino‐2‐hydroxypropoxy part of the compound.