Kindling of the ventral tegmental area induces supersensitivity in the central dopamine system.
Kindling of the ventral tegmental area (VTA), a major source of the mesolimbic dopamine pathway, was examined in rats. We applied two quantitative measurements of dopamine sensitivity before and 2 weeks after VTA kindling (20 times electrical stimulations (100 microA at 1 min intervals) delivered once per day for 14 consecutive days): behavioral responses induced by test VTA stimulation and methamphetamine (MAP)-induced locomotor activity. The total amount of MAP-induced locomotor activity was significantly increased after VTA kindling, while the responses to electrical stimulation were unchanged. These results indicate that repeated activation of the mesolimbic dopamine system can produce a neuroplastic change, which results in dopamine supersensitivity.
Watanabe
Takemi
T
Department of Neuropsychiatry, Faculty of Medicine, Kagawa Medical University, 1750-1 Miki-cho, Kita-gun, Kagawa 761-0793, Japan. 52takemi@kms.ac.jp
Morimoto
Kiyoshi
K
Nakamura
Mitsuo
M
Hirao
Toru
T
Ninomiya
Takashi
T
Ando
Nobuo
N
Suwaki
Hiroshi
H
D000818:Animals; D004298:Dopamine / Q000502:physiology*; D007696:Kindling, Neurologic / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017557:Ventral Tegmental Area / Q000187:drug effects / Q000502:physiology*
D008694:Methamphetamine; D004298:Dopamine