title: Plasticity of the histamine H3 receptors after acute vestibular lesion in the adult cat.
abstract: After unilateral vestibular neurectomy (UVN) many molecular and neurochemical mechanisms underlie the neurophysiological reorganizations occurring in the vestibular nuclei (VN) complex, as well as the behavioral recovery process. As a key regulator, the histaminergic system appears to be a likely candidate because drugs interfering with histamine (HA) neurotransmission facilitate behavioral recovery after vestibular lesion. This study aimed at analyzing the post-lesion changes of the histaminergic system by quantifying binding to histamine H3 receptors (H3R; mediating namely histamine autoinhibition) using a histamine H3 receptor agonist ([(3)H]N-α-methylhistamine). Experiments were done in brain sections of control cats (N = 6) and cats submitted to UVN and killed 1 (N = 6) or 3 (N = 6) weeks after the lesion. UVN induced a bilateral decrease in binding density of the agonist [(3)H]N-α-methylhistamine to H3R in the tuberomammillary nuclei (TMN) at 1 week post-lesion, with a predominant down-regulation in the ipsilateral TMN. The bilateral decrease remained at the 3 weeks survival time and became symmetric. Concerning brainstem structures, binding density in the VN, the prepositus hypoglossi, the subdivisions of the inferior olive decreased unilaterally on the ipsilateral side at 1 week and bilaterally 3 weeks after UVN. Similar changes were observed in the subdivisions of the solitary nucleus only 1 week after the lesion. These findings indicate vestibular lesion induces plasticity of the histamine H3R, which could contribute to vestibular function recovery.
authors.affiliation: Laboratoire de Neurosciences Intégratives et Adaptatives, UMR 7260, FR - Comportement, Cerveau, Cognition (Behavior, Brain, and Cognition), Centre Saint-Charles, Case B, Centre National de la Recherche Scientifique, Aix-Marseille Université Marseille, France.
authors.forename: Brahim
authors.initials: B
authors.lastname: Tighilet
authors.affiliation: Laboratoire de Neurosciences Cognitives, UMR 7291, Centre Saint-Charles, Centre National de la Recherche Scientifique, Aix-Marseille Université Marseille, France.
authors.forename: Christiane
authors.initials: C
authors.lastname: Mourre
authors.affiliation: Laboratoire de Neurosciences Intégratives et Adaptatives, UMR 7260, FR - Comportement, Cerveau, Cognition (Behavior, Brain, and Cognition), Centre Saint-Charles, Case B, Centre National de la Recherche Scientifique, Aix-Marseille Université Marseille, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Lacour
keywords: cat; histamine H3 receptor; inferior olive; solitary nucleus; tuberomammillary nuclei; unilateral vestibular neurectomy; vestibular compensation; vestibular nuclei