title: Subcellular distribution of [14C]5-hydroxytryptamine in the blood platelets of rabbits: effects of imipramine and and haloperidol.
abstract: Long-term (10 days) administration of imipramine [20 mg/(kg X d)] to rabbits significantly increases the Km value (4.0 micron) of 5-hydroxytryptamine uptake in their platelets compared to those of saline- (0.7 micron) or haloperidol- (0.4 micron) treated rabbits. Administration of haloperidol inhibits the 5-hydroxytryptamine uptake non-competitively, and in vitro it had an ID50 value of 22 micron. Intravenous injections of [14C]5-hydroxytryptamine were given to the animals 1 h before blood collection. After isolation of platelets, their sonicates were subjected to 30-60% continuous sucrose gradient centrifugation. The subcellular distribution of [14C]5-hydroxytryptamine indicates that imipramine treatment, in contrast to the control and haloperidol treatment, led to a shift in the exogenous 5-hydroxytryptamine peak from within the granular zone (d 1.18) to the extragranular cytoplasm (d 1.15). Compared to control values, the imipramine treatment caused 63% inhibition in the platelet Na-K-ATPase activity.
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D006220:Haloperidol / Q000494:pharmacology*; D007099:Imipramine / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D011188:Potassium / Q000378:metabolism; D011817:Rabbits; D012701:Serotonin / Q000097:blood*; D012964:Sodium / Q000378:metabolism; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism
chemical_list: D012701:Serotonin; D012964:Sodium; D006220:Haloperidol; D007099:Imipramine; D011188:Potassium