Abstract:
:1. Dopamine efflux following single pulse or train of pulse stimulations was measured in slices of rat caudate putamen, nucleus accumbens and tuberculum olfactorium, using fast cyclic voltammetry at a carbon fibre microelectrode; 1, 5, 10, 20 or 50 pulses were applied at each location at frequencies varying from 10 Hz to 500 Hz. 2. There are significant differences in the ability of the different regions to increase dopamine efflux following single or repeated electrical stimulation. 3. Highest release in response to a single pulse is observed in the caudate putamen (approximately 250 nM dopamine), but the ratio of the peak dopamine overflow following a train of 20 pulses (50 Hz) when compared to a single pulse is rarely greater than three. 4. Release following single pulse stimulation in the nucleus accumbens (approximately 185 nM dopamine) is often slightly less than in the caudate putamen, but the ratio of peak release when trains of 20 pulses (50 Hz) are compared to single pulse stimulation has been as great as seven fold. 5. The tuberculum olfactorium releases the least dopamine of the three regions following a single pulse stimulation (approximately 40 nM dopamine), but the ratio of peak dopamine release following trains of 20 pulses (50 Hz) when compared to single pulse can result in a value approaching 20. 6. When 20 pulses are applied to the caudate putamen at frequencies ranging from 10 to 500 Hz, the peak efflux is essentially the same (frequency/release profile is flat), with the maximum increase only 140% that of a single pulse.7. By contrast, in the nucleus accumbens and the tuberculum olfactorium, well defined frequencyrelease relationships are seen following 20 pulses applied at 10, 20 and 50 Hz; at higher frequencies the dopamine release decreases as frequency is increased.8. Experiments with sulpiride or metoclopramide (dopamine D2 receptor antagonists) indicate that dopamine release in the caudate putamen is not regulated by dopamine autoreceptor activation by endogenous dopamine under our experimental conditions (in the absence of reuptake inhibtion). By contrast, in the nucleus accumbens and in the tuberculum olfactorium, we present evidence to show that at frequencies of stimulation up to 20 Hz, endogenous dopamine acts at dopamine autoreceptors to inhibit further release of dopamine but a minimum exposure time of between 500 and 1000 ms is needed for the response to D2 autoreceptor activation by endogenously released dopamine to be seen.
journal_name
Br J Pharmacoljournal_title
British journal of pharmacologyauthors
Trout SJ,Kruk ZLdoi
10.1111/j.1476-5381.1992.tb14355.xsubject
Has Abstractpub_date
1992-06-01 00:00:00pages
452-8issue
2eissn
0007-1188issn
1476-5381journal_volume
106pub_type
杂志文章abstract::Athletes attempt to improve performance with drugs that act on the beta-adrenergic system directly or indirectly. Of three beta-adrenoceptor (AR) subtypes, the beta(2)-AR is the main target in sport; they have bronchodilator and anabolic actions and enhance anti-inflammatory actions of corticosteroids. Although demons...
journal_title:British journal of pharmacology
pub_type: 杂志文章,评审
doi:10.1038/bjp.2008.164
更新日期:2008-06-01 00:00:00
abstract::1. Effects were studied of 6-(3-dimethylaminopropionyl) forskolin (NKH477), a water-soluble forskolin derivative and of dibutyryl-cyclic AMP, a membrane-permeable cyclic AMP analogue on noradrenaline (NA)-induced Ca2+ mobilization in smooth muscle strips of the rabbit mesenteric artery. The intracellular concentration...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1993.tb13930.x
更新日期:1993-11-01 00:00:00
abstract::1 The effect of potassium channel opening compounds has been investigated in the smooth muscle of rabbit aorta under Ca-free conditions. Examination of the characteristics of the response has been performed using cromakalim as the prototype compound. 2 In order of potency, Ro 31-6930, cromakalim, minoxidil sulphate an...
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pub_type: 杂志文章
doi:10.1111/j.1476-5381.1992.tb13428.x
更新日期:1992-12-01 00:00:00
abstract:BACKGROUND AND PURPOSE:3,4-Methylenedioxymethamphetamine (MDMA or 'Ecstasy') is a worldwide major drug of abuse known to elicit neurotoxic effects. The mechanisms underlying the neurotoxic effects of MDMA are not clear at present, but the metabolism of dopamine and 5-HT by monoamine oxidase (MAO), as well as the hepati...
journal_title:British journal of pharmacology
pub_type: 杂志文章
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abstract::1. The role of both exogenously administered and endogenously generated bradykinin (BK) on LPS-induced eosinophil accumulation in the mice pleural cavity was investigated by means of treatment with BK selective receptor agonists/antagonists and captopril. 2. Intrathoracic (i.t.) injection of LPS (250 ng cavity(-1)) in...
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更新日期:1999-05-01 00:00:00
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更新日期:1996-11-01 00:00:00
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更新日期:2007-10-01 00:00:00
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pub_type: 杂志文章
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更新日期:1995-07-01 00:00:00
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pub_type: 杂志文章
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更新日期:1993-09-01 00:00:00
abstract::1. The aim of this study was to characterize the pharmacological profile of the GABA(B1)/GABA(B2) heterodimeric receptor expressed in Chinese hamster ovary (CHO) cells. We have compared receptor binding affinity and functional activity for a series of agonists and antagonists. 2. The chimeric G-protein, G(qi5), was us...
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更新日期:2000-11-01 00:00:00
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更新日期:2000-09-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1988.tb11490.x
更新日期:1988-04-01 00:00:00
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更新日期:1987-05-01 00:00:00
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更新日期:1977-01-01 00:00:00
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更新日期:2012-03-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1992.tb14259.x
更新日期:1992-02-01 00:00:00
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更新日期:2018-12-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1975.tb07432.x
更新日期:1975-12-01 00:00:00
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更新日期:1983-10-01 00:00:00
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更新日期:2014-07-01 00:00:00
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abstract::1. Rasagiline [N-propargyl-1R(+)-aminoindan], was examined for its monoamine oxidase (MAO) A and B inhibitor activities in rats together with its S(-)-enantiomer (TVP 1022) and the racemic compound (AGN-1135) and compared to selegiline (1-deprenyl). The tissues that were studied for MAO inhibition were the brain, live...
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更新日期:2001-01-01 00:00:00
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更新日期:1999-10-01 00:00:00
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pub_type: 杂志文章,meta分析
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更新日期:2015-09-01 00:00:00
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