title: Distinct changes in peptide YY binding to, and mRNA levels of, Y1 and Y2 receptors in the rat hippocampus associated with kindling epileptogenesis.
abstract: Electrical kindling of the rat dorsal hippocampus induced significant changes in the binding of 125I-peptide YY to Y1 and Y2 subtypes of neuropeptide Y receptors and in their mRNA levels in the area dentata as assessed by quantitative receptor autoradiography and in situ hybridization histochemistry. Binding to Y1 receptor sites decreased by 50% (p < 0.05) in the molecular layer of the stimulated dentate gyrus, 2 days after preconvulsive stage 2 and 1 week or 1 month after generalized stage 5 seizures compared with sham-stimulated rats. Binding to Y2 receptor sites increased bilaterally by 36-87% (p < 0.05) in the hilus at stage 2 and 1 week or 1 month after stage 5. No significant changes were observed after one afterdischarge or in the other hippocampal subfields or in the cortex. Y1 receptor mRNA signal decreased bilaterally by 50-64% (p < 0.01) in the granule cell layer, 6 h but not 24 h after stages 2 and 5. The Y2 receptor mRNA signal was enhanced by 283% (p < 0.01) in the stimulated granule cell layer 24 h after stage 2. At 6 and 24 h after stage 5, mRNA levels were increased both ipsilaterally (283 and 360%, respectively; p < 0.01) and contralaterally (190 and 260%, respectively; p < 0.05). No significant changes in level of either mRNA was found following one afterdischarge. These modifications, and the enhanced neuropeptide Y release previously shown in the hippocampus, suggest that kindling is associated with lasting changes in neuropeptide Y-mediated neurotransmission.
authors.affiliation: Laboratory of Receptor Pharmacology, Mario Negri Institute for Pharmacological Research, Milano, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Gobbi
authors.forename: M
authors.initials: M
authors.lastname: Gariboldi
authors.forename: C
authors.initials: C
authors.lastname: Piwko
authors.forename: D
authors.initials: D
authors.lastname: Hoyer
authors.forename: G
authors.initials: G
authors.lastname: Sperk
authors.forename: A
authors.initials: A
authors.lastname: Vezzani
mesh_terms: D000818:Animals; D001345:Autoradiography; D004827:Epilepsy / Q000209:etiology / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D006651:Histocytochemistry; D017403:In Situ Hybridization; D007696:Kindling, Neurologic; D008297:Male; D019894:Peptide YY / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011964:Receptors, Gastrointestinal Hormone / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D011964:Receptors, Gastrointestinal Hormone; C082172:peptide YY receptor; D019894:Peptide YY