Comparative study of platelet dense granule constituents.
Cat, cattle, dog, horse, human, mink, pig, and rabbit platelets were separated from plasma by gel filtration. The gel-filtered platelets (GFP) were treated with thrombin to induce maximal granule secretion and the potential dense granule constituents ATP, ADP, serotonin (5-HT), Ca2+, and Mg2+ were measured in GFP and in the control and thrombin-treated platelets and in the respective supernatants. The amount of Ca2+, Mg2+, 5-HT, ATP, and ADP within the nonreleasable pool for all species varied between 3.1 and 10.0 mumol/10(11) platelets for Ca2+ and Mg2+ was less than 1.5 mumol/10(11) platelets for ADP and 5-HT and was between 2.0 and 5.0 mumol/10(11) platelets for ATP. Marked differences were observed in the releasable fraction. Human platelets were characterized by the largest releasable Ca2+ pool (greater than 10 mumol/10(11) platelets), the smallest secretable 5-HT and Mg2+ pool (less than 0.5 mumol/10(11) platelets), and the lowest ATP-to-ADP ratio (greater than 1.0). Pig platelets had the highest amount of releasable Mg2+ (approximately 8.0 mumol/10(11) platelets). Rabbits platelets released the most 5-HT (greater than 3.0 mumol/10(11)) and had the highest ATP/ADP (greater than 5.0). The releasable pool of Ca2+, Mg2+, ATP, and ADP in the remaining species varied in mumol/10(11) platelets from approximately 1.5-4.0, approximately 1.0-3.0, 0.5-3.5, and approximately 0.5-1.5, respectively.
D000244:Adenosine Diphosphate / Q000097:blood; D000255:Adenosine Triphosphate / Q000097:blood; D000818:Animals; D001792:Blood Platelets / Q000648:ultrastructure*; D002118:Calcium / Q000097:blood; D002415:Cats; D002417:Cattle; D003594:Cytoplasmic Granules / Q000032:analysis*; D004285:Dogs; D006736:Horses; D006801:Humans; D008274:Magnesium / Q000097:blood; D008907:Mink; D010976:Platelet Count; D011817:Rabbits; D012701:Serotonin / Q000097:blood; D013045:Species Specificity; D013552:Swine
D012701:Serotonin; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D008274:Magnesium; D002118:Calcium