Nursing practice: innovative models.
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Biomedical subjects
Publications and source records attributed to M S Gregory.
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Platelet serotonin uptake was measured in 59 patients with panic attacks and compared to 26 controls. Scatchard analysis of the data showed that the maximal rate of uptake (Vmax) of serotonin was significantly higher in patients than controls. The affinity constant (Km) was not different. In a sub-group of 24 patients, benzodiazepine treatment did not alter the kinetics of platelet serotonin uptake. These findings suggest an abnormality in serotonergic function in patients with panic attacks. Insofar as the platelet is a model of central neuronal function they support serotonergic hyperactivity as a biochemical basis of panic attacks.
The pharmacokinetic properties of a single oral dose of 100 mg of tiapride were studied in six patients with Huntington's disease. The results for five patients were consistent with a two compartment open model. Peak plasma concentrations were observed within 2 h following drug administration with a mean value of 0.92 micrograms/ml being recorded. The drug was rapidly eliminated as unmetabolised tiapride in the urine, 51% of the dose was recovered in 24 h. The plasma elimination half-life was 5.3 h and the average apparent plasma clearance was 16.6 l/h.
Platelet serotonin uptake and 3H-imipramine binding were measured in eight patients with panic disorders and nine controls. The Vmax of serotonin uptake was significantly elevated in patients compared to controls (77 +/- 14 vs. 50 +/- 4 pmol/10(8) platelets/min; P less than 0.05) while Km values were not different (1.46 +/- 0.41 vs. 1.24 +/- 0.20 microM). 3H-Imipramine binding to ruptured platelet membranes was not significantly different between patients and controls for either Bmax (395 +/- 71 vs. 412 +/- 107 fmol/mg protein) or Kd (0.90 +/- 0.18 vs. 1.09 +/- 0.30 nM). The implications for a serotonergic dysfunction in panic disorders are discussed.