Transient changes in nucleus accumbens amino acid concentrations correlate with individual responsivity to the predator fox odor 2,5-dihydro-2,4,5-trimethylthiazoline.
Predator odors elicit fear and defensive behavioral responses in rats, but a wide range of individual responsivity exists. The aim of this study was to examine whether individual differences in behavioral responsivity correlate with differences in amino acid neurotransmission to a predator fox odor, 2,5-dihydro-2,4,5-trimethylthiazoline (TMT). We investigated the time course of behaviorally evoked amino acid neurotransmitter changes in the nucleus accumbens using on-line microdialysis coupled to capillary electrophoresis with 14-s temporal resolution. One subset of animals (high responders) showed a large, biphasic increase in amino acids, such as glutamate and GABA, which lasted about 3 min. These neurochemical changes were highly correlated with increases in locomotion and burrowing, but lagged behind the behavioral changes by 2 min. A second subset of rats (low responders) showed neither behavioral activation nor changes in amino acid neurotransmission. As a positive control, rats were subjected to tail pinch, which evoked transient changes in amino acids in all animals. Cocaine (2 mg/kg, i.v.) increased locomotion but not amino acid levels. This work demonstrates that rapid and transient increases in amino acid neurotransmitters correlate with behavioral reactivity to salient stimuli.
Venton
B Jill
BJ
Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
Robinson
Terry E
TE
Kennedy
Robert T
RT
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D004567:Electrodes, Implanted; D019075:Electrophoresis, Capillary; D005239:Fear; D005243:Feces / Q000737:chemistry; D005589:Foxes / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism; D008297:Male; D017551:Microdialysis; D009043:Motor Activity / Q000187:drug effects; D009714:Nucleus Accumbens / Q000378:metabolism*; D009812:Odorants; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013844:Thiazoles / Q000494:pharmacology*
C411827:2,5-dihydro-2,4,5-trimethylthiazoline; D000596:Amino Acids; D013844:Thiazoles; D018698:Glutamic Acid