Direct monitoring of dopamine and 5-HT release in substantia nigra and ventral tegmental area in vitro
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Direct monitoring of dopamine and 5-HT release in substantia nigra and ventral tegmental area in vitro. / Rice, M E; Richards, C D; Nedergaard, S; Hounsgaard, J; Nicholson, C; Greenfield, S A.
In: Experimental Brain Research, Vol. 100, No. 3, 01.01.1994, p. 395-406.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Direct monitoring of dopamine and 5-HT release in substantia nigra and ventral tegmental area in vitro
AU - Rice, M E
AU - Richards, C D
AU - Nedergaard, S
AU - Hounsgaard, J
AU - Nicholson, C
AU - Greenfield, S A
PY - 1994/1/1
Y1 - 1994/1/1
N2 - Fast-scan cyclic voltammetry with carbon fibre microelectrodes was used to detect endogenous dopamine (DA) and 5-hydroxytryptamine (5-HT) release from three distinct regions of guinea-pig mid-brain in vitro: rostral and caudal substantia nigra (SN) and the ventral tegmental area (VTA). Previous electrophysiological studies have demonstrated that cells of the caudal SN and the VTA have similar characteristics, whereas cells in the rostral SN have distinctly different properties. In the present study, we confirmed that each region has tyrosine hydroxylase-positive neurons and determined, using high-performance liquid chromatography, that DA levels were similar in rostral and caudal SN, but lower in SN than in VTA. In each region, application of veratrine, which was shown by intracellular recordings to have a reversible depolarising action, evoked a signal attributable to DA and distinguishable from that of 5-HT. Release signals were monitored every 250 ms with a spatial resolution of less than 50 microns.l DA release was calcium-dependent and was not detectable in a catecholamine-poor area such as the cerebellum, or in mid-brain tissue pre-treated with reserpine. Within the normal mid-brain, the amount of DA released was correlated with tissue content in that it was higher in the VTA than in either region of SN. It is concluded that DA released from somato-dendritic parts of mid-brain neurons exhibits site-specific variation. This is the first report of direct monitoring of DA and 5-HT release from these regions with in situ electrodes and demonstrates the utility of fast-scan cyclic voltammetry to investigate the mechanisms and possible non-classical functions of somato-dendritic DA release.
AB - Fast-scan cyclic voltammetry with carbon fibre microelectrodes was used to detect endogenous dopamine (DA) and 5-hydroxytryptamine (5-HT) release from three distinct regions of guinea-pig mid-brain in vitro: rostral and caudal substantia nigra (SN) and the ventral tegmental area (VTA). Previous electrophysiological studies have demonstrated that cells of the caudal SN and the VTA have similar characteristics, whereas cells in the rostral SN have distinctly different properties. In the present study, we confirmed that each region has tyrosine hydroxylase-positive neurons and determined, using high-performance liquid chromatography, that DA levels were similar in rostral and caudal SN, but lower in SN than in VTA. In each region, application of veratrine, which was shown by intracellular recordings to have a reversible depolarising action, evoked a signal attributable to DA and distinguishable from that of 5-HT. Release signals were monitored every 250 ms with a spatial resolution of less than 50 microns.l DA release was calcium-dependent and was not detectable in a catecholamine-poor area such as the cerebellum, or in mid-brain tissue pre-treated with reserpine. Within the normal mid-brain, the amount of DA released was correlated with tissue content in that it was higher in the VTA than in either region of SN. It is concluded that DA released from somato-dendritic parts of mid-brain neurons exhibits site-specific variation. This is the first report of direct monitoring of DA and 5-HT release from these regions with in situ electrodes and demonstrates the utility of fast-scan cyclic voltammetry to investigate the mechanisms and possible non-classical functions of somato-dendritic DA release.
KW - Animals
KW - Calcium
KW - Chromatography, High Pressure Liquid
KW - Dendrites
KW - Dopamine
KW - Electrophysiology
KW - Guinea Pigs
KW - Male
KW - Mesencephalon
KW - Microelectrodes
KW - Serotonin
KW - Substantia Nigra
KW - Tegmentum Mesencephali
U2 - 10.1007/BF00229180
DO - 10.1007/BF00229180
M3 - Journal article
C2 - 7813678
VL - 100
SP - 395
EP - 406
JO - Experimental Brain Research
JF - Experimental Brain Research
SN - 0014-4819
IS - 3
ER -
ID: 264288