title: L-tetrahydropalmatine inhibits methamphetamine-induced locomotor activity via regulation of 5-HT neuronal activity and dopamine D3 receptor expression.
abstract: Methamphetamine (METH) is a psychomotor stimulant that produces hyperlocomotion in rodents. l-tetrahydropalmatine (l-THP) is an active ingredient found in Corydalis ternata which has been used as a traditional herbal preparation in Asian countries for centuries, however, the effect of l-THP on METH-induced phenotypes largely unknown. In this study, to evaluate the effect of l-THP on METH-induced psychotropic effects, rats were pretreated with l-THP (10 and 15 mg/kg) before acute METH injection, following which the total distance the rats moved in an hour was measured. To clarify a possible mechanism underlying the effect of l-THP on METH-induced behavioral changes, dopamine receptor mRNA expression levels in the striatum of the rats was measured following the locomotor activity study. In addition, the effect of l-THP (10 and 15 mg/kg) on serotonergic (5-HTergic) neuronal pathway activation was studied by measurement of 5-HT (80 μg/10μl/mouse)-induced head twitch response (HTR) in mice. l-THP administration significantly inhibited both hyperlocomotion in rats and HTR in mice. l-THP inhibited climbing behavior-induced by dopaminergic (DAergic) neuronal activation in mice. Furthermore, l-THP attenuated the decrease in dopamine D3 receptor mRNA expression levels in the striatum of the rats induced by METH. These results suggest that l-THP can ameliorate behavioral phenotype induced by METH through regulation of 5-HT neuronal activity and dopamine D3 receptor expression.
authors.affiliation: Pharmaceutical Standardization Research and Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Republic of Korea. Electronic address: actpotyjs@korea.kr.
authors.forename: Jaesuk
authors.initials: J
authors.lastname: Yun
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001600:Berberine Alkaloids / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D018492:Dopamine Antagonists / Q000494:pharmacology*; D006948:Hyperkinesis / Q000139:chemically induced / Q000188:drug therapy; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology; D008813:Mice, Inbred ICR; D009043:Motor Activity / Q000187:drug effects*; D017207:Rats, Sprague-Dawley; D050637:Receptors, Dopamine D3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology*
chemical_list: D001600:Berberine Alkaloids; D000697:Central Nervous System Stimulants; D018492:Dopamine Antagonists; D050637:Receptors, Dopamine D3; D012702:Serotonin Antagonists; D012701:Serotonin; C014215:tetrahydropalmatine; D008694:Methamphetamine
keywords: 5-HT; Dopamine receptor; Hyperactivity; Levo-tetrahydropalmatine; Methamphetamine