The effects of haloperidol treatment on the distribution of NK1 receptor immunoreactive neurons in guinea-pig brain.
Previous studies have observed increased tachykinin NK(1) receptor immunoreactivity (NK(1)-IR) in the prefrontal cortex in subjects with schizophrenia. Since the subjects were medicated the possibility of a treatment effect could not be excluded. Thus, the present study was undertaken to determine the effect of chronic treatment with the antipsychotic drug, haloperidol, on the distribution of NK(1)-IR neurons in the guinea-pig brain. Guinea pigs were treated each day for 21 days with either haloperidol (1mg/kg) or vehicle and the brains were then processed for immunohistochemistry using an NK(1) receptor-specific polyclonal antibody. NK(1)-IR neurons and fibres were abundant in the forebrain cortex and caudate putamen and more sparsely distributed in a number of other brain regions. The relative density of NK(1)-IR neurons was significantly increased in the forebrain cortex, but not in the caudate putamen in guinea pigs treated with haloperidol. This study has shown that haloperidol causes region-specific changes to the density of NK(1)-IR neurons. Whether these changes are related to the therapeutic effects or to the side effects of haloperidol in individuals with schizophrenia, remains to be determined.
Tooney
Paul A
PA
NISAD, Neuroscience Institute of Schizophrenia and Allied Disorders (NISAD), Sydney, Australia. paul.tooney@newcastle.edu.au
Anderson
Wayne B
WB
Lynch-Frame
Ann
A
Chahl
Loris A
LA
D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D001921:Brain / Q000166:cytology* / Q000187:drug effects; D002452:Cell Count / Q000379:methods; D018491:Dopamine Agonists / Q000494:pharmacology; D004347:Drug Interactions; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006168:Guinea Pigs; D006220:Haloperidol / Q000494:pharmacology*; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D019257:Quinpirole / Q000494:pharmacology; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*; D014018:Tissue Distribution / Q000187:drug effects
D014150:Antipsychotic Agents; D018491:Dopamine Agonists; D018040:Receptors, Neurokinin-1; D019257:Quinpirole; D006220:Haloperidol