title: Amphetamine locomotor sensitization is accompanied with an enhanced high K⁺-stimulated Dopamine release in the rat medial prefrontal cortex.
abstract: In the present work, we assessed dopamine extracellular levels in the medial Prefrontal Cortex of rats repeatedly treated with amphetamine during early abstinence. Rats were injected once daily with amphetamine for five consecutive days. A sensitized locomotor response was observed in 55% of animals treated. After two days of abstinence, an amphetamine challenge dose was given to all rats and locomotor activity was measured to assess expression of sensitization. A persistence of heightened locomotor response to amphetamine was observed in rats that developed sensitization. Twenty four hours after amphetamine challenge, microdialysis experiments were carried out to evaluate basal and stimulated dopamine extracellular levels in the medial Prefrontal Cortex. Rats that developed and expressed amphetamine locomotor sensitization showed a significantly greater high potassium-stimulated dopamine release compared to Non-sensitized and Saline rats. These results show that the increased dopamine releasability in the medial Prefrontal Cortex occurs soon after development of amphetamine locomotor sensitization, and might be underlying the early expression of sensitization.
authors.affiliation: Millenium Science Nucleus in Stress and Addiction, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: José Patricio
authors.initials: JP
authors.lastname: Casanova
authors.forename: Gabriela Paz
authors.initials: GP
authors.lastname: Velis
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Fuentealba
mesh_terms: D000662:Amphetamines / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D008297:Male; D017551:Microdialysis; D009043:Motor Activity; D011188:Potassium / Q000494:pharmacology*; D017397:Prefrontal Cortex / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D000662:Amphetamines; D011188:Potassium; D004298:Dopamine