title: Prenatal ethanol exposure modifies locomotor activity and induces selective changes in Met-enk expression in adolescent rats.
abstract: Several studies suggest that prenatal ethanol exposure (PEE) facilitates ethanol intake. Opioid peptides play a main role in ethanol reinforcement during infancy and adulthood. However, PEE effects upon motor responsiveness elicited by an ethanol challenge and the participation of opioids in these actions remain to be understood. This work assessed the susceptibility of adolescent rats to prenatal and/or postnatal ethanol exposure in terms of behavioral responses, as well as alcohol effects on Met-enk expression in brain areas related to drug reinforcement. Motor parameters (horizontal locomotion, rearings and stereotyped behaviors) in pre- and postnatally ethanol-challenged adolescents were evaluated. Pregnant rats received ethanol (2g/kg) or water during gestational days 17-20. Adolescents at postnatal day 30 (PD30) were tested in a three-trial activity paradigm (habituation, vehicle and drug sessions). Met-enk content was quantitated by radioimmunoassay in several regions: ventral tegmental area [VTA], nucleus accumbens [NAcc], prefrontal cortex [PFC], substantia nigra [SN], caudate-putamen [CP], amygdala, hypothalamus and hippocampus. PEE significantly reduced rearing responses. Ethanol challenge at PD30 decreased horizontal locomotion and showed a tendency to reduce rearings and stereotyped behaviors. PEE increased Met-enk content in the PFC, CP, hypothalamus and hippocampus, but did not alter peptide levels in the amygdala, VTA and NAcc. These findings suggest that PEE selectively modifies behavioral parameters at PD30 and induces specific changes in Met-enk content in regions of the mesocortical and nigrostriatal pathways, the hypothalamus and hippocampus. Prenatal and postnatal ethanol actions on motor activity in adolescents could involve activation of specific neural enkephalinergic pathways.
authors.affiliation: Laboratorio de Psicología Experimental miembro del Centro de Investigación en Psicología (CIPSi), Facultad de Psicología, Universidad Nacional de Córdoba, CP 5000 Córdoba, Argentina; Enfermera Gordillo esq. Enrique Barros, Ciudad Universitaria, CP 5000 Córdoba, Argentina. Electronic address: pabate@unc.edu.ar.
authors.forename: P
authors.initials: P
authors.lastname: Abate
authors.affiliation: Departamento de Neuroquímica, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría Ramón de la Fuente, Calzada México Xochimilco 101, Col. San Lorenzo Huipulco, CP 14370 Ciudad de México, Mexico.
authors.forename: A C
authors.initials: AC
authors.lastname: Reyes-Guzmán
authors.affiliation: Departamento de Neuroquímica, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría Ramón de la Fuente, Calzada México Xochimilco 101, Col. San Lorenzo Huipulco, CP 14370 Ciudad de México, Mexico.
authors.forename: K
authors.initials: K
authors.lastname: Hernández-Fonseca
authors.affiliation: Departamento de Neuroquímica, Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría Ramón de la Fuente, Calzada México Xochimilco 101, Col. San Lorenzo Huipulco, CP 14370 Ciudad de México, Mexico. Electronic address: ubach@imp.edu.mx.
authors.forename: M
authors.initials: M
authors.lastname: Méndez
mesh_terms: D000375:Aging; D000679:Amygdala / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D010450:Endopeptidases / Q000378:metabolism*; D000431:Ethanol / Q000494:pharmacology*; D005260:Female; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D008124:Locomotion / Q000187:drug effects*; D009714:Nucleus Accumbens / Q000187:drug effects*; D017397:Prefrontal Cortex / Q000187:drug effects; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000378:metabolism; D017208:Rats, Wistar; D017557:Ventral Tegmental Area / Q000187:drug effects*
chemical_list: D000431:Ethanol; D010450:Endopeptidases; C027374:Met-enk forming enzyme
keywords: Adolescence; Enkephalins; Ethanol-induced locomotor activity; Ontogeny; Opioid peptides