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Effects of Intranigral Substance P and Neurokinin A Injections on Extracellular Dopamine Levels Measured with Microdialysis in the Striatum and Frontoparietal Cortex of Rats
Author(s) -
Reid Malcolm S.,
HerreraMarschitz Mario,
Ungerstedt Urban
Publication year - 1991
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1991.tb08245.x
Subject(s) - microdialysis , striatum , dopamine , chemistry , medicine , substance p , endocrinology , basal ganglia , amphetamine , cortex (anatomy) , 3,4 dihydroxyphenylacetic acid , cerebral cortex , central nervous system , neuropeptide , neuroscience , biology , homovanillic acid , receptor , serotonin
Extracellular levels of dopamine (DA) and its metabolite, 3,4‐dihydroxyphenylacetic acid (DOPAC), in the striatum and frontoparietal (sensorimotor) cortex in halo‐ thane‐anesthetized rats were analyzed simultaneously using in vivo microdialysis. Basal DA levels, measured from the microdialysis perfusate, were 6.4 ± 0.8 n M (n = 15) in the striatum and 0.9 ± 0.1 n M (n = 15) in the frontoparietal cortex. Subcutaneous injections of d ‐amphetamine (2 mg/kg) increased DA levels 10‐fold in the striatum and fivefold in the cortex. Injections of substance P (0.07 nmol/0.2 μl) into the substantia nigra pars reticulata (SNR) increased DA and DOPAC levels ∼30% in the ipsilateral striatum and 50% in the ipsilateral frontoparietal cortex. Injections of neurokinin A (0.09 nmol/0.2 μ l) into the SNR increased DA and DOPAC levels ∼30% in the ipsilateral striatum but did not significantly affect DA levels in the ipsilateral frontoparietal cortex, although DOPAC levels were increased by ∼50%. It is suggested that striatal and cortical DA release is regulated differently by nigral substance P and neurokinin A terminals.