Phosphodiesterase isoenzymes in equine platelets and their influence on platelet adhesion.
OBJECTIVE
To determine the phosphodiesterase (PDE) isoenzymes in equine platelets and evaluate their influence on platelet adhesion.


METHODS
Platelets obtained from healthy New Forest Pony geldings that ranged from 12 to 20 years of age (mean +/- SEM, 17.3 +/- 1.1 years).


METHODS
PDE isoenzyme activity in equine platelets was determined by use of a 2-step radioactive assay. Functional importance of PDE isoenzymes was established by use of selective inhibitors in a colorimetric adhesion assay.


RESULTS
PDE1, PDE2, PDE3, and PDE5 and small amounts of PDE4 were found in equine platelets. Inhibition of PDE3 abolished platelet adhesion almost completely, whereas inhibition of PDE4 and PDE5 had little effect.


CONCLUSIONS
Function of equine platelets can be influenced by inhibition of PDE3. Selective PDE3 inhibitors may be clinically useful to regulate platelet function. They offer the advantage of increased potency with fewer adverse effects, compared with those for nonselective PDE inhibitors.
Department of Veterinary Basic Sciences, The Royal Veterinary College, North Mymms, Herts, England.
Bettina
B
Dunkel
Karen J
KJ
Rickards
Clive P
CP
Page
Fiona M
FM
Cunningham
D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000201:enzymology*; D002448:Cell Adhesion / Q000502:physiology*; D002478:Cells, Cultured; D019583:Dose Fractionation, Radiation; D006736:Horses / Q000097:blood*; D007527:Isoenzymes / Q000378:metabolism; D008297:Male; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology
D007527:Isoenzymes; D010975:Platelet Aggregation Inhibitors; D010727:Phosphoric Diester Hydrolases