Effects of drugs acting on adrenergic and adenosine receptors on the intraocular pressure and the activity of adenylyl cyclase in ciliary processes and their sensitivity to pertussis toxin.
The effects of the selective alpha2-adrenergic agonist p-aminoclonidine, the nonselective adrenergic agonist epinephrine, the selective beta2-adrenergic agonist fenoterol and the adenosine A1 agonist R-PIA on intraocular pressure were studied in control and pertussis toxin-pretreated rabbits. Pretreatment of rabbits with pertussis toxin decreased the ocular hypotensive effects of p-aminoclonidine and epinephrine, did not influence the same effects of fenoterol or R-PIA and markedly potentiated the initial ocular hypertensive effects of epinephrine and R-PIA. As far as the action on adenylyl cyclase in ciliary processes is concerned, isoproterenol stimulated its activity in control rabbits and epinephrine exerted dual, i.e. stimulatory and inhibitory effects on the activity of this enzyme. The data obtained with epinephrine and p-aminoclonidine confirm the view that their ocular hypotensive effects are associated with their inhibitory action on adenylyl cyclase and contradict the opinion that the hypotensive action of adrenergic drugs depends on adenylyl cyclase activation.
Cepelík
J
J
Institute of Pharmacology, First Faculty of Medicine, Charles University, Prague, Czech Republic.
Caicedo
M
M
Dedina
M
M
Hynie
S
S
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D037361:Adenylate Cyclase Toxin; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000322:Adrenergic Agonists / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D002924:Ciliary Body / Q000187:drug effects / Q000201:enzymology*; D003000:Clonidine / Q000031:analogs & derivatives / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D005280:Fenoterol / Q000494:pharmacology; D007429:Intraocular Pressure / Q000187:drug effects*; D037342:Pertussis Toxin; D058906:Purinergic P1 Receptor Agonists; D011817:Rabbits; D011941:Receptors, Adrenergic / Q000187:drug effects / Q000502:physiology*; D018047:Receptors, Purinergic P1 / Q000187:drug effects / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*; D015016:Yohimbine / Q000494:pharmacology
D037361:Adenylate Cyclase Toxin; D000322:Adrenergic Agonists; D000317:Adrenergic alpha-Antagonists; D058906:Purinergic P1 Receptor Agonists; D011941:Receptors, Adrenergic; D018047:Receptors, Purinergic P1; D010566:Virulence Factors, Bordetella; C047235:N-(1-methyl-2-phenylethyl)adenosine; D005280:Fenoterol; D015016:Yohimbine; C016986:apraclonidine; D037342:Pertussis Toxin; D000262:Adenylyl Cyclases; D000241:Adenosine; D003000:Clonidine; D004837:Epinephrine