[The effect of phosphodiesterase type 3 inhibitor on chorio-retinal blood flow in rabbits eyes].
OBJECTIVE
To investigate the ocular effect of intravenous administration of a phosphodiesterase type 3 inhibitor (NSP-805) and to compare the effect of NSP-805 with that of a calcium antagonist (nicardipine hydrochloride) on chorio-retinal blood flow in anesthetized albino rabbits.


METHODS
Twenty-four female albino rabbits (weighting 2.0-4.0 kg) were anesthetized with intravenous injection. NSP-805(40 micrograms/kg and 100 micrograms/kg) and nicardipine of 40 micrograms/kg were intravenously administrated to the anesthetized rabbits. Intravenously administration of 20% dimethyl sulfoxide (DMSO) was used as a vehicle. Chorio-retinal blood flow was measured with a laser Doppler flowmeter at baseline and every 20 minutes after intravenous administration for 120 minutes. Heart rates and systemic blood pressure were monitored. Baseline measurements were compared with every 10 minutes after intravenous administration. Differences between the drug groups and vehicle group were analyzed.


RESULTS
After administration of a low dose of NSP--805 (40 micrograms/kg) and nicardipine (40 micrograms/kg), the chorio-retinal blood flow was significantly increased (p < 0.05). A high dose NSP-805(100 micrograms/kg) reduced systemic blood pressure significantly, but the increase of chorio-retinal blood flow was less than that at the low dose of NSP-805(40 micrograms/kg) and nicardipine (40 micrograms/kg). Chorio-retinal blood flow in the NSP 805(40 micrograms/kg) and nicardipine (40 micrograms/kg) groups was significantly increased over that in the control group (20% DMSO) (p < 0.05).


CONCLUSIONS
The results suggest that the NSP-805 has the potential of increasing chorio-retinal blood flow in rabbit eyes.
Uchida
Hideya
H
Department of Ophthalmology, Gifu University School of Medicine, 40 Tsukasa-machi, Gifu 500-8705, Japan.
Tomita
Goji
G
Hoshina
Futoshi
F
Mochizuki
Nobuo
N
Kitazawa
Yoshiaki
Y
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors*; D000818:Animals; D002829:Choroid / Q000098:blood supply*; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D005260:Female; D017078:Laser-Doppler Flowmetry; D009529:Nicardipine / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D011724:Pyridazines / Q000494:pharmacology*; D011817:Rabbits; D012160:Retina / Q000187:drug effects*
D010726:Phosphodiesterase Inhibitors; D011724:Pyridazines; C082248:NSP 805; D009529:Nicardipine; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3