Abstract
The aim of the present study was to examine the influence of 3-month administration of haloperidol (1 mg/kg per day) and clozapine (30 mg/kg per day) in drinking water on cortical NMDA (N-methyl-d-aspartate) receptors in rats. On day 5 of withdrawal, the animals were killed and their brains were removed. The binding of [3H]MK-801 ([3H](5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d] cyclohepten-5,10-imine) and [3H]CGP 39653 ([3H]d,l-(E)-2-amino-4-propyl-5-phosphono-3-pentenoic acid) to NMDA receptors in different cortical areas, as well as the binding of [3H]spiperone to dopamine D2 receptors in the striatum, were analysed by quantitative autoradiography. Haloperidol increased the binding of [3H]CGP 39653 in frontal, insular and parietal cortices. Clozapine increased the binding of [3H]CGP 39653 in insular and parietal cortices. Haloperidol, but not clozapine, increased the binding of [3H]spiperone in the striatum. None of the neuroleptics influenced the binding of [3H]MK-801 to cortical NMDA receptors. An additional assay revealed an increase in the B max value, with no significant changes in the K D of [3H]CGP 39653 binding in parieto-insular cortical homo-genates as a result of haloperidol and clozapine administration.
The present results suggest that long-term treatments with haloperidol and clozapine increase the number of NMDA receptors in different cortical regions.
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Received: 15 September 1998 / Accepted: 25 January 1999
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Ossowska, K., Pietraszek, M., Wardas, J. et al. Chronic haloperidol and clozapine administration increases the number of cortical NMDA receptors in rats. Naunyn-Schmiedeberg's Arch Pharmacol 359, 280–287 (1999). https://doi.org/10.1007/PL00005353
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DOI: https://doi.org/10.1007/PL00005353