Infusions of acetaldehyde into the arcuate nucleus of the hypothalamus induce motor activity in rats.
OBJECTIVE
The hypothalamic arcuate nucleus (ARH) is one of the brain regions with the highest levels of catalase expression. Acetaldehyde, metabolized from ethanol in the CNS through the actions of catalase, has a role in the behavioral effects observed after ethanol administration. In previous studies acetaldehyde injected in the lateral ventricles or in the substantia nigra reticulata (SNR) mimicked the behavioral stimulant effects of centrally administered ethanol.


METHODS
In the present study we assessed the effects of acetaldehyde administered either into the ARH into a dorsal control or into the third ventricle on locomotion and rearing observed in 30 min sessions in an open field.


RESULTS
Acetaldehyde injected into the ARH induced horizontal locomotion and rearing for 20 min. In contrast, administration of acetaldehyde into a control site dorsal to the ARH did not have any effect on locomotion. Although acetaldehyde administration into the third ventricle also induced locomotion, the time course for the effect in this area was different from the time course following ARH injections. Acetaldehyde in the ARH produced a long lasting induction of locomotion, while with intraventricular injections the effects disappeared after 5 min.


CONCLUSIONS
The present results are consistent with previous studies demonstrating that acetaldehyde is an active metabolite of ethanol, which can have locomotor stimulant properties when administered in the ventricular system of the brain or into specific brain nuclei. Some brain nuclei rich in catalase (i.e.; SNR and ARH) could be mediating some of the locomotor stimulant effects of ethanol through its conversion to acetaldehyde.
Correa
Mercè
M
Department of Psychology, University of Connecticut, Storrs, CT, 06269-1020, USA; Area de Psicobiologia, Universitat Jaume I, 12071 Castelló, Spain. correa@psb.uji.es
Arizzi-Lafrance
Maria N
MN
Salamone
John D
JD
D000079:Acetaldehyde / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D001522:Behavior, Animal / Q000187:drug effects; D000431:Ethanol / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D007263:Infusions, Parenteral; D007276:Injections, Intraventricular; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000431:Ethanol; D000079:Acetaldehyde