Increased platelet membrane [3H]‐LSD binding in patients on chronic neuroleptic treatment.

Abstract

This was probably due to the persistence of the neuroleptic in the platelet membrane preparation. 4 There was a weak positive correlation between receptor number and total neuroleptic dosage. 5 The increased number of 5-HT receptors is consistent with the previously reported enhancement of 5-HT-induced platelet aggregation in patients treated with long-term phenothiazines and thioxanthenes. 6 Our findings are compatible with 5-HT up-regulation in human platelets produced by depot neuroleptic therapy. It is not known whether parallel changes may be occurring in brain 5-HT receptors.

Serotonin 5-HT2A Receptor Binding in Platelets from Healthy Subjects as Studied by [3H]-Lysergic Acid Diethylamide ([3H]-LSD): Intra- and Interindividual Variability

“…Our results are similar to the means reported by Norman et al (1990), McBride et al (1987, and Sheline et al (1995), but lower than those reported by Steckler et al (1993), Arora and Meltzer (1989a), Geaney et al (1984), Cowen et al (1986), Schachter et al (1985), and Pandey et al (1990Pandey et al ( , 1993. The median Kct of 0.81 nM in the present study is similar to the means reported by Cowen et al (1986) and Meltzer (1989a, 1993), but somewhat higher than those found by Schachter et al (1985), Norman et al (1990), Steckler et al (1993), Geaney et al (1984) and Sheline et al (1995), and somewhat lower than reported by McBride et al (1987McBride et al ( , 1994. Mean Kd values in healthy subjects in earlier studies have varied between 0.5 nM (Geaney et al 1984;Norman et al 1990) and 1.7 nM (McBride et al 1994).…”

Effect of Clozapine Treatment on Serotonin-2—Receptor Binding in the Blood Platelets of Schizophrenic Patients

“…The results reported here with typical neuroleptic drugs are in partial agreement with those reported by Schachter et al (1985) who reported an increase in Kd as well as Bmax of 5-HT2 receptor binding in schizo phrenic patients receiving depot neuroleptic treatment. Schachter et al (1985) speculated that neuroleptic-in duced increases in Kd may be due to drug retension during preparation of platelet membranes.…”

“…Schachter et al (1985) speculated that neuroleptic-in duced increases in Kd may be due to drug retension during preparation of platelet membranes. The proce dure of Geaney et al (1984) for preparing platelet mem branes was utilized both in this study and in that of Schachter et al (1985). Furthermore, platelet mem branes were prepared the same way for both typical and atypical (clozapine)-antipsychotic drug treated pa tients.…”

“…No signifIcant group difference was observed between schizophrenic pa tients and normal controls (Arora and Meltzer 1993). Schachter et al (1985) reported increased Kd and Bmax of 5-HT2 binding in the blood platelets of neuroleptic (fluphenazine, flupenthixol, clopenthixol, chlorproma zine)-treated schizophrenic patients. We have now studied the effect of chronic clozapine treatment on 5-HT2 receptor binding in the blood platelets of schizo phrenic patients.…”

The relationship of pineal calcification and melatonin secretion to the pathophysiology of tardive dyskinesia and tourette's syndrome

“…These receptors are located postsynaptically and mediate certain 5-HT induced behaviors in animals (Peroutka et al, 1981). In schizophrenic patients on long-term neuroleptics, the number of binding sites on the platelet for (3H) LSD is increased (Schachter et al, 1985), suggesting that 5-HT2 receptors in the periphery may be upregulated by chronic neuroleptic treatment. Moreover,Von Hungen et al (1 975) have shown that chlorpromazine inhibits the activity of 5-HT stimulated adenylate cyclase as does cyproheptadine, a 5-HT antagonist.…”