Showing 3 results for Dopamine
Mirzaii Dizgah I, Karimian M, Zarrindast M.r, Sohanaki H,
Volume 65, Issue 3 (6-2007)
Abstract
Background: Opiate-induced addiction is a main social problem in Iran. As treatment of this problem is a health priority among the medical community, studies on this topic are very crucial. The exact mechanism of dependence on opiates and their withdrawal syndrome remain unclear. It seems that dopaminergic system and locus coeruleus (LC) have an important role in the expression of somatic signs during opioids withdrawal. The LC has been shown to contain significant levels of dopamine (DA). In the present study, the effects of different D2 dopaminergic receptor agonist and antagonist administration in the LC on withdrawal sign expression in morphine dependence is investigated in rats.
Methods: Adult male Wistar rats, weighing 220–280 g were divided into eight groups (n=8). Two cannulae were stereotaxically implanted bilaterally into the LC of each rat. After a one-week recovery, seven groups were rendered dependent on morphine by subcutaneous injection during a seven-day period. Non-dependent control animals received saline according to the same protocol. Animals received bilateral intra-LC injections of saline (1 μg/site) and quinpirole (0.1, 0.3 and 0.5 μg/site, a D2 agonist) 15 min and sulpiride (5, 15 and 30 μg/site, a D2 antagonist) 30 min prior to naloxone injection about 24 hours after the last dose of morphine or saline according to their respective group. To calculate the total withdrawal score, as an index of withdrawal syndrome, 20 different withdrawal signs were assessed and the scores of the intensity of these withdrawal signs were added.
Results: Total withdrawal scores were significantly decreased by quinpirole (0.1µg/site) and sulpiride (15 and 30 µg/site).
Conclusion: The D2 dopaminergic system in the LC may be involved in the morphine-induced dependency in rats. Further studies are needed to define the mechanism of this dependency in order to improve methods for the rehabilitation of addicts.
Sabzehkhah S, Vaezi Gh H, Bakhtiarian A, Salarian A, Zare Haghighi M,
Volume 67, Issue 8 (11-2009)
Abstract
Background: Dopaminergic is the most important
neurotransmitter is fear. The dopaminergic mesolimbic pathway has essential
role in excitable behavior, and it's role in Parkinson disease. The aim of this
research in study, the effect of dopaminergic pathway in fear response.
Methods: The elevated plus maze was used in
combination with the percentage of time spent in the open arms of the maze (OAT%) and the percentage of entries into the
open arms (OAE%) to measure fear. Increases in the OAT% and OAE% indicate an anxiolytic effect
(reduction in anxiety), whereas decreases in the OAE% and OAT% indicate an anxiogenic effect. After
five days, the rats were injected with saline and different doses of sulpiride
and Bromocriptine.
Results: Results showed that intracerebroventricular
administration of sulpiride, in the doses of 5, 20μg/rat and bromocriptine, D2 agonist in doses 65, 95μg/rat produced
a significant effect comparing to sham groups (p<0.05). While intracerebroventricular
administration of sulpiride 15, 10μg/rat,
and bromocriptine 70,
80μg/rat,
did not show any significant effect comparing with sham group (p<0.05). In the current research
intracerebroventricular administration of sulpiride, D2 antagonist at the doses of 5, 10, 15, 20μg/rat and Bromocriptine, D2 agonist in the doses of 65, 70, 80, 95μg/rat were used and theire effect on
the fear behavior were studied.
Conclusions: The possible effect of Dopaminergic
system in the fear process, especially D2 receptor increase fear.
Hatam Ahmadi , Parvin Rostami , Mohammad Reza Zarrindast, Mohammad Nasehi , Homa Mohseni Kochesfehani ,
Volume 71, Issue 3 (6-2013)
Abstract
Background: Nucleus accumbens (NAc) and prefrontal cortex (PFC) dopaminergic and glutamatergic systems are involved in regulating of locomotor activity behaviors. This study has investigated the interaction of NAc shell dopaminergic system and prelimbic glutamatergic systems in regulating locomotor activity and related parameters.
Methods: The aim of this study was the effect the drugs injection interaction in the brain of male Wistar rats on locomotor activity and related parameters, in the order of this purpose, open field apparatus that automatically recorded locomotor activity was employed. Unilateral intra-cerebral injection of drugs was done.
Results: Unilateral intra-prelimbic injection of D-AP7 (N-methyl-D-aspartic acid= NMDA receptor antagonist 0.25, 0.5 and 1μg/μl) did not alter locomotor activity behaviors. However, infusion of NMDA (0.9μg/μl) in this region increased locomotor activity (P<0.01), whereas decreased rearing (P<0.01) and grooming (P<0.01) which was blocked by D-AP7 (0.25μg/μl) (P<0.01). Moreover, unilateral infusion of SCH23390 (dopamine D1 receptor antagonist 0.25, 0.5 and 1μg/μl) into the left NAc shell did not alter locomotor activity. However, injection of SKF38393 (dopamine D1 receptor agonist 4μg/μl) into the left NAc shell increased locomotor activity (P<0.05) which was blocked by SCH23390 (0.25μg/μl) (P<0.01). Furthermore, the subthreshold dose infusion of SCH23390 (0.25μg/μl) into the left NAc shell reduced the effect of intra- prelimbic NMDA on locomotor activity (P<0.01). In addition, intra-NAc shell administration of the subthreshold dose of SKF38393 (1μg/μl) potentiated the middle dose (P<0.05), whereas decreased the higher dose of intra-left prelimbic NMDA response (P<0.05) on locomotor activity.
Conclusion: The results suggested a modulatory effect of the NAc shell dopaminergic system on increased locomotor activity by activating glutamate system in prelimbic.
