Premium
Differential effect of immobilization stress on in vivo synthesis rate of monoamines in medial prefrontal cortex and nucleus accumbens of conscious rats
Author(s) -
Nakahara Daiichiro,
Nakamura Masato
Publication year - 1999
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/(sici)1098-2396(19990601)32:3<238::aid-syn9>3.0.co;2-x
Subject(s) - nucleus accumbens , microdialysis , prefrontal cortex , chemistry , dopamine , in vivo , monoamine neurotransmitter , catecholamine , neuroscience , serotonin , endocrinology , extracellular , medicine , biochemistry , biology , receptor , cognition , microbiology and biotechnology
We have used microdialysis to measure the in vivo hydroxylation level of tyrosine and tryptophan in the medial prefrontal cortex and nucleus accumbens of conscious rats that were subjected to immobilization. The brain was perfused with an inhibitor of aromatic l ‐amino acid decarboxylase, 3‐hydroxybenzylhydrazine, and the amount of 3,4‐dihydroxyphenylalanine (DOPA) and 5‐hydroxytryptophan (5‐HTP) accumulating in the dialysate was measured as an index of the in vivo hydroxylation rate of tyrosine and tryptophan. One hour of immobilization caused a significant increase in extracellular DOPA in the medial prefrontal cortex but not nucleus accumbens. The same manipulation produced a significant and more prolonged elevation in extracellular 5‐HTP in the nucleus accumbens as well as medial prefrontal cortex. The observed profile of stress‐induced 5‐HTP response was comparable in two brain regions. The results suggest that in vivo catecholamine synthesis is heterogenous, whereas in vivo serotonin synthesis is homogenous, with respect to responsiveness to stress in the medial prefrontal cortex and nucleus accumbens. Synapse 32:238–242, 1999. © 1999 Wiley‐Liss, Inc.