title: Glutamatergic neurotransmission in the inferior colliculus influences intrastriatal haloperidol-induced catalepsy.
abstract: The inferior colliculus (IC) is an important midbrain relay station for the integration of descending and ascending auditory information. In addition, it has also been implicated in the processing of acoustic information of aversive nature, as well as in sensory-motor gating. There is evidence that glutamate-mediated mechanisms at the IC level influence haloperidol-induced catalepsy. The present study investigated the influence of glutamate-mediated mechanisms in the IC on catalepsy induced by intrastriatal microinjection of haloperidol (10 μg/0.5 μl). Male Wistar rats received bilateral intracollicular microinjections of the glutamate receptor agonist NMDA (10 or 20 nmol/0.5 μl), the NMDA receptor antagonists MK-801 (15 or 30 nmol/0.5 μl) or physiological saline (0.5 μl), followed by bilateral microinjections of haloperidol (10 μg/0.5 μl) or vehicle (0.5 μl) into the dorso-rostral or ventro-rostral striatum. The catalepsy test was performed positioning both forepaws of the rats on an elevated horizontal wooden bar and recording the time during which the animal remained in this position. The results showed that the administration of physiological saline in the IC followed by the microinjection of haloperidol in the dorso-rostral region of the striatum was not able to induce catalepsy. However, when the bilateral administration of NMDA into the IC was followed by microinjection of haloperidol into the dorso-rostral striatum, catalepsy was observed. The microinjection of haloperidol into the ventro-rostral striatum induced catalepsy, counteracted by previous administration of MK-801 into the IC. These findings suggest that glutamate-mediated mechanisms in the IC can influence the intrastriatal haloperidol-induced catalepsy and that the IC plays an important role as a sensorimotor interface.
authors.affiliation: Departamento de Biociências, Universidade Federal de São Paulo, Av. D. Ana Costa, 95, Vila Mathias, Santos 11060-001, SP, Brasil.
authors.forename: P
authors.initials: P
authors.lastname: Medeiros
authors.affiliation: Departamento de Biociências, Universidade Federal de São Paulo, Av. D. Ana Costa, 95, Vila Mathias, Santos 11060-001, SP, Brasil.
authors.forename: M B
authors.initials: MB
authors.lastname: Viana
authors.affiliation: Departamento de Biociências, Universidade Federal de São Paulo, Av. D. Ana Costa, 95, Vila Mathias, Santos 11060-001, SP, Brasil.
authors.forename: R C
authors.initials: RC
authors.lastname: Barbosa-Silva
authors.affiliation: Departamento de Biociências, Universidade Federal de São Paulo, Av. D. Ana Costa, 95, Vila Mathias, Santos 11060-001, SP, Brasil.
authors.forename: L C
authors.initials: LC
authors.lastname: Tonelli
authors.affiliation: Departamento de Biociências, Universidade Federal de São Paulo, Av. D. Ana Costa, 95, Vila Mathias, Santos 11060-001, SP, Brasil; Instituto de Neurociências & Comportamento-INEC, Campus USP, Ribeirão Preto 14040-901, SP, Brasil. Electronic address: lianamel@gmail.com.
authors.forename: L
authors.initials: L
authors.lastname: Melo-Thomas
mesh_terms: D000818:Animals; D014150:Antipsychotic Agents / Q000009:adverse effects*; D002375:Catalepsy / Q000139:chemically induced* / Q000503:physiopathology; D003342:Corpus Striatum / Q000187:drug effects / Q000503:physiopathology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism*; D006220:Haloperidol / Q000009:adverse effects*; D007245:Inferior Colliculi / Q000187:drug effects* / Q000503:physiopathology*; D008297:Male; D016202:N-Methylaspartate / Q000378:metabolism; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
chemical_list: D014150:Antipsychotic Agents; D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D018698:Glutamic Acid; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D006220:Haloperidol
keywords: Catalepsy; Glutamate; Haloperidol; Inferior colliclus; NMDA; Striatum