Adrenergic Influence on the Ciliary Muscle and the Outflow Facility of Enucleated Bovine Eyes

In an effort to understand the aqueous outflow mechanism, the author compared changes in the outflow facility with the response of ciliary muscle, using fresh bovine eyes. Neither epinephrine nor isoproterenol alone increased the outflow facility, regardless of their concentrations. However, theophylline, caffeine, isobutylmethylxanthine (IBMX), and other phosphodiesterase (PDE) inhibitors, increased facility in a dose-dependent manner. Epinephrine alone did neither relax the tone nor inhibit the nerve-mediated contraction of bovine ciliary muscle. Theophylline and IBMX relaxed the tone and inhibited the nerve-mediated contraction, whereas, N-ethylmaleimide, iodoacetamide and iodoacetic acid inhibited the nerve-mediated contraction, and they elevated the tone of ciliary muscle. All PDE inhibitors tested increased the outflow facility and inhibited the nerve-mediated contractions, however, the effect of such drugs on the ciliary muscle tone varied. These results suggest that PDE inhibition plays much more greater influence on and around the outflow channels, from the viewpoint of facility change of outflow and ciliary muscle contraction.

房水流出率

交感神経関連薬

phosphodiesterase 抑制薬

毛様体筋