title: Acute vigorous exercise primes enhanced NO release in human platelets.
abstract: Activation of platelets by acute vigorous exercise has been demonstrated by various parameters, including an increase in agonist-induced platelet [Ca2+]i levels. However, direct evidence is lacking regarding how acute exercise affects platelet-derived NO. Twenty-three healthy male non-smokers (21-59 years) underwent a symptom-limited treadmill exercise test. Washed platelets were prepared from blood samples obtained before and immediately after exercise. All subjects completed at least Bruce stage 2 and were each negative for ischemia. With a low dose (2 microg/ml) of collagen, NO release from washed platelets, detected by the NO-selective microelectrode, was significantly increased after exercise (pmols/10(8) platelets, before: 0.64+/-0.11, after: 1.03+/-0.18; P<0.005) without changes in aggregation ability. This enhanced NO release was accompanied by increased platelet [Ca2+]i levels (before: 232+/-25, after: 296+/-37; P<0.01). With a high dose (5 or 10 microg/ml) of collagen, NO release and aggregation were both modestly, but significantly, enhanced after exercise. The exercise-induced enhancement of platelet NO release in response to collagen was also suggested by increase in platelet cyclic guanosine monophosphate accumulation and augmenting effect of N(G)-monomethyl-L-arginine on platelet aggregation. In summary, acute strenuous exercise primes enhanced NO release and may play a protective role against exercise-induced activation of platelets in normal subjects.
authors.affiliation: Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-Ku, Tokyo 113-8519, Japan.
authors.forename: Natsuko
authors.initials: N
authors.lastname: Kasuya
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kishi
authors.forename: Shin-ya
authors.initials: SY
authors.lastname: Sakita
authors.forename: Fujio
authors.initials: F
authors.lastname: Numano
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Isobe
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000097:blood; D003094:Collagen / Q000494:pharmacology; D006152:Cyclic GMP / Q000097:blood; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000097:blood*; D010974:Platelet Aggregation / Q000187:drug effects; D012016:Reference Values; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D003094:Collagen; D006152:Cyclic GMP; D002118:Calcium