R. Suzuki et al., EFFECTS OF ADRENERGIC AGENTS AND PHOSPHODIESTERASE INHIBITORS ON OUTFLOW FACILITY AND CELL-SHAPE OF BOVINE TRABECULAR MESHWORK, Japanese Journal of Ophthalmology, 41(1), 1997, pp. 31-37
Changes in the outflow facility of perfused calf eyes and in the shape
of cells in cultured trabecular meshwork (TM) have been studied, foll
owing exposure to adrenergic agents and phosphodiesterase inhibitors (
PDE). Dobutamine caused confluent TM cells to change their usual polyg
onal shape to a characteristic stellate shape. Salbutamol had no effec
t, but PDE: inhibitors, isobutylmethylxanthine (IBMX), theophylline, a
nd caffeine were very effective in producing this shape change. Epinep
hrine, isoproterenol, dobutamine, and salbutamol did not increase the
outflow facility, either at 22 degrees C or 36 degrees C, while theoph
ylline, caffeine, and IBMX did increase it in a dose-dependent manner.
On the other hand, the high concentrations of beta-adrenergic agents
required to produce even a small change in outflow facility and cell s
hape argue against the involvement of adrenergic-receptor mediation an
d may suggest another mechanism; on the other, the enhancement of epin
ephrine effects by PDE inhibitors and the similar effect produced by c
yclic adenosine 3',5'-cyclic phosphate (cAMP) and purines suggest that
changes in the cell shape are produced by beta-receptor activation. T
he beta-adrenergic agents were not effective in changing outflow facil
ity, but the PDE inhibitors were remarkably effective both in changing
the shape and in increasing facility. (C) 1997 Japanese Ophthalmologi
cal Society.