scholarly journals Imaging cocaine-induced changes in the mesocorticolimbic dopaminergic system of conscious rats

2004 ◽  
Vol 139 (2) ◽  
pp. 167-176 ◽  
Author(s):  
Marcelo Febo ◽  
Annabell C. Segarra ◽  
Jeffrey R. Tenney ◽  
Mathew E. Brevard ◽  
Timothy Q. Duong ◽  
...  
Keyword(s):  
Dopaminergic System ◽  
Conscious Rats ◽  
Induced Changes ◽  
Mesocorticolimbic Dopaminergic System

Model explaining the relation between distal nephron Li+ reabsorption and urinary Na+ excretion in rats

1998 ◽  
Vol 274 (3) ◽  
pp. F445-F452 ◽  
Author(s):  
Michael Shalmi ◽  
Thomas Jonassen ◽  
Klaus Thomsen ◽  
Jonathan D. Kibble ◽  
Peter Bie ◽  
...  
Keyword(s):  
Urinary Excretion ◽  
Apical Membrane ◽  
Fractional Excretion ◽  
Distal Nephron ◽  
Conscious Rats ◽  
Angiotensin Iii ◽  
Collecting Ducts ◽  
Induced Changes ◽  
Different Levels

Li+ may be reabsorbed via an amiloride-sensitive mechanism in the collecting ducts of rats administered a low-Na+ diet. This was investigated by measuring the increase in fractional urinary excretion of Li+(FELi) in response to amiloride in conscious rats at two different levels of plasma Li+ concentration and after administration of bendroflumethiazide (BFTZ), angiotensin III (ANG III), and aldosterone (Aldo). The results confirmed that amiloride increased (FELi) in rats on a low-Na+ diet (20 ± 1 to 35 ± 1%, means ± SE), whereas no increase was observed in rats on a normal Na+ diet (37 ± 1 to 38 ± 1%). The lithiuretic effect of amiloride was 1) abolished by preadministration of BFTZ (32 ± 1 to 33 ± 2%) to Na+-deprived rats and 2) increased by ANG III (27 ± 3 to 33 ± 2%) and Aldo (25 ± 2 to 37 ± 2%) in Na+-replete rats. Amiloride-induced changes in FELiwere independent of plasma Li+concentration but inversely related to the fractional excretion of Na+ and the amiloride-sensitive excretion of K+. These results are compatible with the hypothesis that a low tubular Na+ concentration reduces end-tubular Na+ reabsorption and results in hyperpolarization of the apical membrane, thus favoring Li+ uptake into the cells.

Photoperiodic modulation of the dopaminergic control of pulsatile LH secretion in sheep

1994 ◽  
Vol 143 (1) ◽  
pp. 25-32 ◽  
Author(s):  
D J Tortonese ◽  
G A Lincoln
Keyword(s):  
Dopaminergic System ◽  
Pulse Frequency ◽  
Inhibitory System ◽  
Pulsatile Gnrh ◽  
Photoperiodic Regulation ◽  
Series Of Experiments ◽  
Induced Changes ◽  
Lh Secretion ◽  
Short Days ◽  
Sustained Increase

Abstract This study was conducted to investigate whether the photoperiodic regulation of the seasonal changes in pulsatile LH secretion in the ram involves changes in the activity of inhibitory hypothalamic dopaminergic (DA) pathways. To test this hypothesis, a series of experiments was carried out in Soay rams in which the effects of a DA-D2 receptor antagonist (sulpiride) or a DA-D2 receptor agonist (bromocriptine) on the pulsatile secretion of LH were determined under both long and short days. In each experiment blood samples were collected every 10 min for 8 h starting at the time of vehicle, sulpiride or bromocriptine injections to assess concentrations of LH. Sulpiride (0·59 mg/kg, s.c.) administered to rams under long days induced an immediate and sustained increase in the secretion of LH that lasted for approximately 4 h (P<0·05; ANOVA); this LH response reflected both a rise in mean concentrations (0·247 ± 0·03 vs.0·452 ± 0·1 μg/1) and an increase in the frequency of LH pulses (0·5±0·5 vs. 2·33±0·42 pulses/8 h; P<0·01). In contrast, under short days sulpiride had no effect. Bromocriptine (0·06 mg/kg, s.c.) administered to rams under long days, when LH concentrations were low, was without effect, but when given to rams under short days significantly (P<0·05) suppressed mean LH concentrations (0·627 ±0·08 vs. 0·320 ± 0·02 μg/l) and LH pulse frequency (4·86 ±0·46 vs. 2·43 ±0·37 pulses/8 h). In an additional experiment, pimozide (total dose: 0·16 mg/kg, i.m.), a DA antagonist less specific for DA-D2 receptors than sulpiride, was ineffective in modifying LH secretion in sexually inactive rams exposed to long days. These results are consistent with the hypothesis that an inhibitory dopaminergic system is involved in the regulation of pulsatile LH secretion in the ram. The induced changes in LH pulse frequency under long days (increased by sulpiride) and under short days (decreased by bromocriptine) indicate that, under both photoperiods, DA acts within the hypothalamus, via a specific DA-D2 receptor, to influence pulsatile GnRH secretion. A photoperiodic-induced activation of this inhibitory system may therefore represent the mechanism whereby long days suppress LH secretion and lead to the sexually inactive state characteristic of the non-breeding season. Journal of Endocrinology (1994) 143, 25–32

scholarly journals Role of TAAR1 within the Subregions of the Mesocorticolimbic Dopaminergic System in Cocaine-Seeking Behavior

2017 ◽  
Vol 37 (4) ◽  
pp. 882-892 ◽  
Author(s):  
Jian-Feng Liu ◽  
Justin N. Siemian ◽  
Robert Seaman ◽  
Yanan Zhang ◽  
Jun-Xu Li
Keyword(s):  
Dopaminergic System ◽  
Cocaine Seeking ◽  
Seeking Behavior ◽  
Mesocorticolimbic Dopaminergic System

Relatively spared mesocorticolimbic dopaminergic system in juvenile parkinsonism

2007 ◽  
Vol 13 (8) ◽  
pp. 483-488 ◽  
Author(s):  
Nahoko Yoshimura ◽  
Masayuki Yokochi ◽  
Yayoi Kan ◽  
Shinichi Koyama ◽  
Mitsuru Kawamura
Keyword(s):  
Dopaminergic System ◽  
Juvenile Parkinsonism ◽  
Mesocorticolimbic Dopaminergic System
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