Platelet serotonin content and uptake in spontaneously hypertensive rats.
Platelet serotonin (5-HT) content and uptake were studied in male SHR and WKY at various ages. Blood was withdrawn from the carotid artery under anesthesia and 5-HT levels determined from platelet rich plasma (PRP) using a HPLC technique coupled with an electrochemical detection method. Platelet 5-HT uptake was studied by incubating PRP at 37 degrees C for 10 sec with increasing concentrations of 3H-5HT. Lineweaver- Burk plots of 3H-5HT uptake were linear suggesting simple Michaelis- Menten uptake kinetics. The SHR had more platelets than age-matched controls and consequently a higher blood circulating pool of 5-HT. Nevertheless, the 5-HT platelet levels were similar to those of their age-matched rats. The 5 week-old SHR and WKY had greater numbers of platelets and higher 5-HT platelet levels than the older rats of both strains. The affinity constants (Km) and the maximal velocities (Vmax) of platelet 5-HT uptake did not differ significantly between the 12 week- and the 6 month-old SHR and WKY. These data suggest that the SHR do not show the same impairment in platelet 5-HT metabolism as observed in essential hypertension in man.
D000367:Age Factors; D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D006973:Hypertension / Q000097:blood*; D007700:Kinetics; D008297:Male; D010976:Platelet Count; D051381:Rats; D011918:Rats, Inbred SHR; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000097:blood*
D012701:Serotonin