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Evidence for co-release of noradrenaline and dopamine from noradrenergic neurons in the cerebral cortex.
Mol Psychiatry. 2001 Nov; 6(6):657-64.MP

Abstract

The aim of this study was to determine whether extracellular dopamine (DA) in the prefrontal cortex (PFC) might originate other than from DA neurons, also from noradrenergic (NA) ones. To this aim, we compared the levels of DA and NA in the dialysates from the PFC, a cortical area innervated by NA and DA neurons, and cortices that receive NA but minor or no DA projections such as the primary motor, the occipital-retrosplenial, and the cerebellar cortex. Moreover, the effect of alpha(2)-ligands and D(2)-ligands that distinctly modify NA and DA neuronal activity on extracellular NA and DA in these areas was studied. Extracellular NA concentrations were found to be similar in the different cortices, as expected from the homogeneous NA innervation, however, unexpectedly, also DA concentrations in the PFC were not significantly different from those in the other cortices. The alpha(2)-adrenoceptor agonist clonidine, intraperitoneally (i.p.) injected or locally perfused into the PFC, reduced not only extracellular NA levels, as expected from its ability to inhibit NA neuron activity, but also markedly reduced extracellular DA levels. Conversely, the alpha(2)-adrenoceptor antagonist idazoxan, i.p. injected or locally perfused into the PFC, not only increased extracellular NA levels, in line with its ability to activate NA neuron activity, but also increased those of DA. Conversely, in contrast to its ability to inhibit DA neuronal activity, the D(2) receptor agonist quinpirole only modestly and transiently reduced extracellular DA levels, while gamma-butyrolactone failed to modify DA levels in the PFC; conversely, haloperidol, at variance from its ability to activate DA neurons, failed to significantly modify extracellular DA levels in the PFC. Both haloperidol and quinpirole were totally ineffective after local perfusion into the PFC. Systemically injected or locally perfused, clonidine and idazoxan also modified both DA and NA concentrations in dialysates from primary motor, occipital-retrosplenial and cerebellar cortices as observed in the PFC. Finally, i.p. injected or locally perfused, clonidine reduced and idazoxan increased extracellular NA levels in the caudate nucleus, but neither alpha(2)-ligand significantly modified extracellular DA levels. Our results suggest that extracellular DA in the PFC, as well as in the other cortices, may depend on NA rather than DA innervation and activity. They suggest that dialysate DA reflects the amine released from NA neurons as well, where DA acts not only as NA precursor but also as co-transmitter. The co-release of NA and DA seems to be controlled by alpha(2)-receptors located on NA nerve terminals.

Authors+Show Affiliations

Department of Neuroscience BB Brodie, University of Cagliari, via Porcell 4, I-09124 Cagliari, Italy. pdevoto@unica.itNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

11673793

Citation

Devoto, P, et al. "Evidence for Co-release of Noradrenaline and Dopamine From Noradrenergic Neurons in the Cerebral Cortex." Molecular Psychiatry, vol. 6, no. 6, 2001, pp. 657-64.
Devoto P, Flore G, Pani L, et al. Evidence for co-release of noradrenaline and dopamine from noradrenergic neurons in the cerebral cortex. Mol Psychiatry. 2001;6(6):657-64.
Devoto, P., Flore, G., Pani, L., & Gessa, G. L. (2001). Evidence for co-release of noradrenaline and dopamine from noradrenergic neurons in the cerebral cortex. Molecular Psychiatry, 6(6), 657-64.
Devoto P, et al. Evidence for Co-release of Noradrenaline and Dopamine From Noradrenergic Neurons in the Cerebral Cortex. Mol Psychiatry. 2001;6(6):657-64. PubMed PMID: 11673793.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Evidence for co-release of noradrenaline and dopamine from noradrenergic neurons in the cerebral cortex. AU - Devoto,P, AU - Flore,G, AU - Pani,L, AU - Gessa,G L, PY - 2000/09/13/received PY - 2001/02/12/revised PY - 2001/02/12/accepted PY - 2001/10/24/pubmed PY - 2002/1/24/medline PY - 2001/10/24/entrez SP - 657 EP - 64 JF - Molecular psychiatry JO - Mol Psychiatry VL - 6 IS - 6 N2 - The aim of this study was to determine whether extracellular dopamine (DA) in the prefrontal cortex (PFC) might originate other than from DA neurons, also from noradrenergic (NA) ones. To this aim, we compared the levels of DA and NA in the dialysates from the PFC, a cortical area innervated by NA and DA neurons, and cortices that receive NA but minor or no DA projections such as the primary motor, the occipital-retrosplenial, and the cerebellar cortex. Moreover, the effect of alpha(2)-ligands and D(2)-ligands that distinctly modify NA and DA neuronal activity on extracellular NA and DA in these areas was studied. Extracellular NA concentrations were found to be similar in the different cortices, as expected from the homogeneous NA innervation, however, unexpectedly, also DA concentrations in the PFC were not significantly different from those in the other cortices. The alpha(2)-adrenoceptor agonist clonidine, intraperitoneally (i.p.) injected or locally perfused into the PFC, reduced not only extracellular NA levels, as expected from its ability to inhibit NA neuron activity, but also markedly reduced extracellular DA levels. Conversely, the alpha(2)-adrenoceptor antagonist idazoxan, i.p. injected or locally perfused into the PFC, not only increased extracellular NA levels, in line with its ability to activate NA neuron activity, but also increased those of DA. Conversely, in contrast to its ability to inhibit DA neuronal activity, the D(2) receptor agonist quinpirole only modestly and transiently reduced extracellular DA levels, while gamma-butyrolactone failed to modify DA levels in the PFC; conversely, haloperidol, at variance from its ability to activate DA neurons, failed to significantly modify extracellular DA levels in the PFC. Both haloperidol and quinpirole were totally ineffective after local perfusion into the PFC. Systemically injected or locally perfused, clonidine and idazoxan also modified both DA and NA concentrations in dialysates from primary motor, occipital-retrosplenial and cerebellar cortices as observed in the PFC. Finally, i.p. injected or locally perfused, clonidine reduced and idazoxan increased extracellular NA levels in the caudate nucleus, but neither alpha(2)-ligand significantly modified extracellular DA levels. Our results suggest that extracellular DA in the PFC, as well as in the other cortices, may depend on NA rather than DA innervation and activity. They suggest that dialysate DA reflects the amine released from NA neurons as well, where DA acts not only as NA precursor but also as co-transmitter. The co-release of NA and DA seems to be controlled by alpha(2)-receptors located on NA nerve terminals. SN - 1359-4184 UR - https://www.unboundmedicine.com/medline/citation/11673793/Evidence_for_co_release_of_noradrenaline_and_dopamine_from_noradrenergic_neurons_in_the_cerebral_cortex_ L2 - https://doi.org/10.1038/sj.mp.4000904 DB - PRIME DP - Unbound Medicine ER -