title: Role of dopaminergic DAD1 and DAD2 receptors in the sensitization of amphetamine-suppressed schedule-induced polydipsia in rats.
abstract: Effects of dopaminergic D1 (DAD1) and D2 (DAD2) receptors were examined in the sensitization of amphetamine (AMPH)-suppressed schedule-induced polydipsia (SIP). After training under a fixed-interval 60 sec schedule of food presentation in the presence of a water tube, rats received injections of different doses of AMPH 10 min prior to the test. It was found that AMPH at 2.0 mg/kg significantly to reduced licks and water intake during the SIP. The AMPH-suppressed SIP manifested again following 5-days of pretreatment with a sub-threshold dosage of AMPH (1.0 mg/kg) and a period of withdrawal. The role of dopaminergic D1 and D2 receptors was then examined by introducing D1 or D2 antagonist during the 5-days repeated injections of a sub-threshold dosage of AMPH. Results showed that DAD1 antagonist SCH23390 had little effect on the sensitization. However pretreatment with DAD2 antagonist haloperidol (HAL) prevented the sensitization to AMPH in the long-term rather than short-term withdrawal conditions. It is suggested that SIP could be a useful paradigm to study AMPH sensitization in rats and the involvement of dopamine receptors might be different.
authors.affiliation: Department of Physiology and Biophysics, National Defense Medical Center, Taipei, Taiwan, Republic of China.
authors.forename: Yia-Ping
authors.initials: YP
authors.lastname: Liu
authors.forename: Pai-Jone
authors.initials: PJ
authors.lastname: Lin
authors.forename: Ching-Jiunn
authors.initials: CJ
authors.lastname: Tseng
authors.forename: Fang-Jung
authors.initials: FJ
authors.lastname: Wan
authors.forename: Che-Se
authors.initials: CS
authors.lastname: Tung
mesh_terms: D000661:Amphetamine / Q000009:adverse effects* / Q000494:pharmacology; D019969:Amphetamine-Related Disorders / Q000209:etiology / Q000503:physiopathology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D001552:Benzazepines / Q000494:pharmacology; D015259:Dopamine Agents / Q000009:adverse effects* / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D065127:Dopamine D2 Receptor Antagonists; D004305:Dose-Response Relationship, Drug; D004327:Drinking Behavior / Q000187:drug effects / Q000502:physiology*; D006220:Haloperidol / Q000494:pharmacology; D008124:Locomotion / Q000502:physiology; D008297:Male; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors / Q000502:physiology*; D017448:Receptors, Dopamine D2 / Q000502:physiology*
chemical_list: D001552:Benzazepines; D015259:Dopamine Agents; D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; C534628:SCH 23390; D000661:Amphetamine; D006220:Haloperidol