Amphetamine-induced hyperlocomotion in rats: Hippocampal modulation of the nucleus accumbens.
Using lesions and infusions, the present study investigated the way in which and the extent to which the ventral hippocampus (vHIP) modulates amphetamine-induced hyperactivity in rats. Rats were lesioned (excitotoxic or sham) in the vHIP or were implanted with cannulae for subsequent infusions. A high dose (12.5 microg/microl) of N-methyl-D-aspartate (NMDA) was used to make excitotoxic lesions and a low dose (0.5 microg/microl) of NMDA to cause activation of the hippocampus. Lidocaine was used to inactivate the hippocampus. Lidocaine or a low dose of NMDA was infused into the vHIP in combination with either systemic injection or intra-accumbens infusions of amphetamine. The effects of these treatments on locomotor activity were measured by distance traveled in 10-min intervals for 40-60 min. Lesions and deactivation of the hippocampus attenuated amphetamine-induced hyperlocomotion, compared to the controls. Stimulation of the hippocampus augmented amphetamine-induced hyperlocomotion. The present findings provide evidence that the hippocampus exerts excitatory modulation on the expression of behavioral excitation produced by amphetamine, likely via the nucleus accumbens.
White
Ilsun M
IM
Department of Psychology, Morehead State University, Morehead, Kentucky 40351, USA. i.white@morehead-st.edu
Whitaker
Christopher
C
White
Wesley
W
D000661:Amphetamine / Q000494:pharmacology*; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003714:Denervation; D004298:Dopamine / Q000502:physiology; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity; D006624:Hippocampus / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D016202:N-Methylaspartate / Q000633:toxicity; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D009434:Neural Pathways; D009714:Nucleus Accumbens / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
D000779:Anesthetics, Local; D000697:Central Nervous System Stimulants; D018690:Excitatory Amino Acid Agonists; D016202:N-Methylaspartate; D008012:Lidocaine; D000661:Amphetamine; D004298:Dopamine