dihydroergotoxine and Myotonic-Dystrophy

Platelet function tests were performed on 11 patients with myotonic dystrophy of Steinert (MD) and on 21 healthy control subjects. Using citrated platelet-rich plasma or washed platelets, MD patients had normal aggregation and secretion responses after stimulation with adrenaline, ADP, collagen, PAF, arachidonic acid and thrombin. Using intact and functional washed platelets, MD patients responded normally to adrenaline and had a similar affinity and number of alpha 2-adrenergic receptors as control patients as measured by [3H]dihydroergocryptine and [3H]yohimbine binding. In addition platelets from MD patients had normal basal and stimulated levels of cytoplasmic free Ca2+ as measured with the fluorescent Ca2+ probe quin2. Thus platelet functions, alpha 2-adrenergic receptors and cytoplasmic free Ca2+ are normal in MD.

Topics: Adenosine Diphosphate; Adult; Blood Platelets; Blood Proteins; Calcium; Cytoplasm; Dihydroergotoxine; Epinephrine; Female; Hemostasis; Humans; In Vitro Techniques; Male; Middle Aged; Myotonic Dystrophy; Platelet Adhesiveness; Platelet Aggregation; Platelet Function Tests; Receptors, Adrenergic, alpha; Serotonin; Yohimbine