beta-Adrenergic agonist-induced nitrite production in isolated pig ciliary processes.
BACKGROUND
We performed an experiment to assess whether in ciliary processes adrenergic-receptor agents can modulate the production of nitrite, an oxidized metabolite of nitric oxide (NO).


METHODS
The porcine ciliary processes and the iris were dissected and stored at -20 degrees C. Later, tissues were thawed, and nitrite measured by Griess reaction, before and 2 h after exposure to various drugs.


RESULTS
In the ciliary processes, but not in the iris, the alpha-, beta-adrenergic receptor agonist, norepinephrine (0.01-10 microM), increased nitrite production (95 +/- 12%, P < 0.01). The norepinephrine-induced (0.1 microM) nitrite production was inhibited by the inhibitor of NO synthase, N omega-nitro-L-arginine methyl ester (0.5 mM; P < 0.05) and by the non-selective beta-adrenergic receptor antagonist, propranolol (10 microM; P < 0.01), but not by the non-selective alpha-adrenergic receptor antagonist, phentolamine (10 microM).


CONCLUSIONS
In isolated porcine ciliary processes, beta-adrenergic receptor stimulation increases NO production.
Liu
R
R
Laboratory of Ocular Pharmacology and Physiology, University Eye Clinic, Basel, Switzerland.
Flammer
J
J
Lüscher
T F
TF
Haefliger
I O
IO
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002924:Ciliary Body / Q000187:drug effects* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009573:Nitrites / Q000378:metabolism*; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D013552:Swine
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D004791:Enzyme Inhibitors; D009573:Nitrites; D011943:Receptors, Adrenergic, beta; D009569:Nitric Oxide; D011433:Propranolol; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester; D009638:Norepinephrine