Effect of chronic haloperidol treatment on peripheral benzodiazepine binding sites in cerebral cortex of rats

Abstract

The effects of 21 days of haloperidol treatment on central benzodiazepine (BZ) receptors in the cerebral cortex of rats and on peripheral-type BZ binding sites (PBS) in the cerebral cortex and heart of rats were studied. Neuroleptic treatment did not affect the maximal binding capacity or the affinity of the central BZ receptor to 3H-flunitrazepam. Chronic haloperidol treatment resulted in a significant increase of 38% in PBS density in the cerebral cortex, with no alteration in PBS density in the heart. No alteration in PBS affinity for its ligand 3H-PK 11195 was observed, either in the cerebral cortex or in the heart. The modulatory effect of chronic haloperidol administration on PBS density in the brain may be related to some of the neurobehavioral or hormonal effects of the drug.

No Evidence of Altered In Vivo Benzodiazepine Receptor Binding in Schizophrenia

“…In the present study, we failed to replicate these results, since no regional differences in BDZ V T were observed between patients on or off neuroleptics. Thus our results do not support alteration of BDZ receptors density associated with longterm neuroleptic exposure, a conclusion consistent with preclinical studies (Gavish et al 1988;Giardino et al 1991).…”

“…Patient clinical evaluation at intake included the Positive and Negative Symptoms Scales (PANS) (Kay et al 1987), a scale that includes the Brief Psychiatric Rating Scale (BPRS) (Overall and Gorham 1962), and the AIMS (Munetz and Benjamin 1988). Since BDZ receptor density is not consistently affected by chronic antipsychotic administration (Gavish et al 1988;Giardino et al 1991), neuroleptic withdrawal was not required for this study.…”

Effects of Chronic Chlorpromazine Treatment on Peripheral Benzodiazepine Binding Sites in Heart, Kidney, and Cerebral Cortex of Rats

“…Previous studies have demonstrated that repeated CPZ administration can cause an increase in GABA binding in the substantia nigra but not in the striatum (Gale, 1980u,b;Huffman and Ticku, 1983). The lack of effect of chronic CPZ treatment on cortical CBRs, as demonstrated in the present study, is similar to that found in previous studies in which no alteration in r3H]FNZ binding in the cerebral cortex of rats was achieved with chronic haloperidol treatment (Pazo et al, 1987;Gavish et al, 1988).…”

Autoradiographic analysis of regional alterations in brain receptors following chronic administration and withdrawal of typical and atypical neuroleptics in rats

“…In contrast to the [3H]muscimol results, no significant changes were seen in benzodiazepine receptor binding after neuroleptic treatment, thus suggesting the possibility of specific changes at the GABA binding site, but not the benzodiazepine site. The only previous studies that have looked at benzodiazepine receptor binding (using [3H]flunitrazepam) after prolonged neuroleptic treatment reported no alterations in benzodiazepine binding in the cortex or striatum, although a decrease in the cerebellum was found (Rupniak et al, 1987;Gavish et al, 1988).…”