Long-term treatment with haloperidol affects neuropeptide S and NPSR mRNA levels in the rat brain

OBJECTIVE: The brainstem-derived neuropeptide S (NPS) has a multidirectional regulatory activity, especially as a potent anxiolytic factor. Accumulating data suggests that neuroleptics affect peptidergic signalling in various brain structures. However, there is no information regarding the influence of haloperidol on NPS and NPS receptor (NPSR) expression. METHODS: We assessed NPS and NPSR mRNA levels in brains of rats treated with haloperidol using quantitative real-time polymerase chain reaction. RESULTS: Chronic haloperidol treatment (4 weeks) led to a striking upregulation of NPS and NPSR expression in the rat brainstem. Conversely, the NPSR mRNA expression was decreased in the hippocampus and striatum. CONCLUSIONS: This stark increase of NPS in response to haloperidol treatment supports the hypothesis that this neuropeptide is involved in the dopamine-dependent anxiolytic actions of neuroleptics and possibly also in the pathophysiology of mental disorders. Furthermore, our findings underline the complex nature of potential interactions between dopamine receptors and brain peptidergic pathways, which has potential clinical applications

Extended neuroleptic administration modulates NMDA-R subunit immunoexpression in the rat neocortex and diencephalon

Background This study aimed to evaluate the effect of extended olanzapine, clozapine and haloperidol administration on NMDA-R subunit immunoexpression in the rat neocortex and diencephalon. Methods To explore NR1, NR2A and NR2B subunit protein expression, densytometric analysis of immunohistochemically stained brain slices was performed. Results Interestingly, all neuroleptics caused a downregulation of NMDA-R subunit expression in the thalamus but increased the level of NR1 in the hypothalamus. Olanzapine upregulated hypothalamic NR2A expression, while clozapine and haloperidol decreased hypothalamic levels. We observed no significant changes in NR2B immunoreactivity. None of the studied medications had significant influence on NMDA-R subunit expression in the neocortex. Conclusions Neuroleptic-induced reduction in the expression of thalamic NMDA-R subunits may play an important role in the regulation of glutamatergic transmission disorders in cortico–striato–thalamo–cortical loop in schizophrenia. A decrease in NMDA signaling in this region after long-term neuroleptic administration may also cautiously explain the incomplete effectiveness of these drugs in the therapy of schizophrenia-related cognitive disturbances

Escitalopram affects spexin expression in the rat hypothalamus, hippocampus and striatum

Background Spexin (SPX) is a recently discovered neuropeptide that exhibits a large spectrum of central and peripheral regulatory activity, especially when considered as a potent anorexigenic factor. It has already been proven that antidepressants, including selective serotonin reuptake inhibitors (SSRI), can modulate peptidergic signaling in various brain structures. Despite these findings, there is so far no information regarding the influence of treatment with the SSRI antidepressant escitalopram on brain SPX expression. Methods In this current study we measured SPX mRNA and protein expression in the selected brain structures (hypothalamus, hippocampus and striatum) of rats chronically treated with a 10 mg/kg dose of escitalopram using quantitative Real-Time PCR and immunohistochemistry. Results Strikingly, long-term (4 week) drug treatment led to the downregulation of SPX expression in the rat hypothalamus. This supports the hypothesis that SPX may be involved in the hypothalamic serotonin-dependent actions of SSRI antidepressants and possibly also in the central mechanism of body mass increase. Conversely, SPX expression increased in the hippocampus and striatum. Conclusions This is the first report of the effects of a neuropsychiatric medication on SPX expression in animal brain. Our findings shed a new light on the pharmacology of antidepressants and may contribute to a better understanding of the alternative mechanisms responsible for antidepressant action

Long-term treatment with olanzapine increases the number of Sox2 and doublecortin expressing cells in the adult subventricular zone

Continuously active neurogenic regions in the adult brain are located in the subventricular zone (SVZ) of the lateral ventricles and subgranular zone (SGZ) of the hippocampal dentate gyrus. Neurogenesis is modulated by many factors such as growth factors, neurotransmitters and hormones. Neuropsychiatric drugs, especially antidepressants, mood stabilizers and antipsychotics may also affect the origin of neuronal cells. The purpose of this study was to determine the effects of chronic olanzapine treatment on adult rat neurogenesis at the level of the SVZ. The number of neuroblasts was evaluated using immunohistochemical and fluorescent detection of sex determining region Y-box 2 (Sox-2) and doublecortin (DCX) expressing cells. The results indicate that olanzapine has proneurogenic effects in the adult rat SVZ, as the mean number of sex determining region Y-box 2 (Sox-2) and doublecortin-positive cells increased significantly, while there was a similar tendency in the subgranular zone SGZ. Collectively, these results suggest that long-term treatment with olanzapine may stimulate neurogenic stem cell formation in the SVZ which supports adult neurogenesis

Efect of long‑term treatment with classical neuroleptics on NPQ/ spexin, kisspeptin and POMC mRNA expression in the male rat amygdala

Neuroleptics modulate the expression level of some regulatory neuropeptides in the brain. However, if these therapeutics infuence the peptidergic circuits in the amygdala remains unclear. This study specifes the impact profle of the classical antipsychotic drugs on mRNA expression of the spexin/NPQ, kisspeptin-1 and POMC in the rat amygdala. Animals were treated with haloperidol and chlorpromazine for 28 days prior to transcript quantifcation via qPCR. Haloperidol and chlorpromazine induced a change in the expression of all neuropeptides analyzed. Both drugs led to the decrease of Kiss-1 expression, whereas in POMC and spexin/NPQ their up-regulation in the amygdala was detected. These modulating efects on may represent alternative, so far unknown mechanisms, of classical antipsychotic drugs triggering pharmacological response