Effects of dopamine partial-agonist aminoergolines on dopamine metabolism in limbic and extrapyramidal regions of rat brain

Baldessarini, Ross J.; Marsh, Elda R.; Huston-Lyons, David

doi:10.1016/0006-2952(94)90323-9

Cited by 5 publications

(2 citation statements)

References 9 publications

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“…In the “open-loop” model, it is possible for dopaminergic drugs to modify dopamine synthesis via long-loop feedback pathways; whereas, γ-butyrolactone is used in the “closed-loop” model to inhibit nerve impulse flow, thus dopamine agonists and antagonists can only modify dopamine synthesis through autoreceptor-mediated actions (Walters and Roth, 1976). As expected, γ-butyrolactone, when administered alone, increased dopamine synthesis in the dorsal striatum of adolescent and adult rats (see also Walters and Roth, 1976; Shalaby et al, 1981; Baldessarini et al, 1994; Andersen et al, 1997). Regardless of the model employed, stimulating D 2 autoreceptors with quinpirole inhibited dopamine synthesis in both age groups (Svensson et al, 1991; Andersen et al, 1997; Heidbreder and Baumann 2001; Der-Ghazarian et al, 2010).…”

Section: Discussionsupporting

confidence: 80%

“…After 25 min, groups were further subdivided with rats being injected with distilled water or the nerve impulse inhibitor γ-butyrolactone (PD 28, 625 mg/kg; PD 91, 750 mg/kg, i.p.). Although 750 mg/kg γ-butyrolactone is commonly administered to adult rats (Walters and Roth, 1976; Svensson et al, 1991; Baldessarini et al, 1994), a lower dose of the drug was given to PD 28 rats because 750 mg/kg γ-butyrolactone, when combined with haloperidol, frequently causes respiratory failure in younger animals. After an additional 5 min, all rats were injected with the DOPA decarboxylase inhibitor NSD-1015 (100 mg/kg, i.p.).…”

Section: Methodsmentioning

confidence: 99%

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Postnatal manganese exposure does not alter dopamine autoreceptor sensitivity in adult and adolescent male rats

McDougall

Mohd-Yusof

Kaplan

et al. 2013

European Journal of Pharmacology

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Administering manganese chloride (Mn) to rats on postnatal day (PD) 1–21 causes long-term reductions in dopamine transporter levels in the dorsal striatum, as well as persistent increases in D1 and D2 receptor concentrations. Whether dopamine autoreceptors change in number or sensitivity is uncertain, although D2S receptors, which may be presynaptic in origin, are elevated in Mn-exposed rats. The purpose of this study was to determine if early Mn exposure causes long-term changes in dopamine autoreceptor sensitivity that persist into adolescence and adulthood. To this end, male rats were exposed to Mn on PD 1–21 and autoreceptor functioning was tested 7 or 70 days later by measuring (a) dopamine synthesis (i.e., DOPA accumulation) in the dorsal striatum after quinpirole or haloperidol treatment and (b) behavioral responsiveness after low-dose apomorphine treatment. Results showed that low doses (i.e., “autoreceptor” doses) of apomorphine (0.06 and 0.12 mg/kg) decreased the locomotor activity of adolescent and adult rats, while higher doses increased locomotion. The dopamine synthesis experiment also produced classic autoreceptor effects, because quinpirole decreased dorsal striatal DOPA accumulation; whereas, haloperidol increased DOPA levels in control rats, but not in rats given the nerve impulse inhibitor γ-butyrolactone. Importantly, early Mn exposure did not alter autoreceptor sensitivity when assessed in early adolescence or adulthood. The lack of Mn-induced effects was evident in both the dopamine synthesis and behavioral experiments. When considered together with past studies, it is clear that early Mn exposure alters the functioning of various dopaminergic presynaptic mechanisms, while dopamine autoreceptors remain unimpaired.

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Section: Discussionsupporting

confidence: 80%

Section: Methodsmentioning

confidence: 99%

Postnatal manganese exposure does not alter dopamine autoreceptor sensitivity in adult and adolescent male rats

McDougall

Mohd-Yusof

Kaplan

et al. 2013

European Journal of Pharmacology

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Effects of aripiprazole and terguride on dopamine synthesis in the dorsal striatum and medial prefrontal cortex of preweanling rats

et al. 2007

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Effects of repeated and acute aripiprazole or haloperidol treatment on dopamine synthesis in the dorsal striatum of young rats: comparison to adult rats

et al. 2010

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The purpose of the present study was to determine whether repeated treatment with the D2 partial agonist aripiprazole or the D2 antagonist haloperidol alters dopamine (DA) synthesis characteristics in the dorsal striatum of young rats. To this end, rats received a daily pretreatment regimen of aripiprazole or haloperidol on postnatal days (PD) 10-20 and were tested 24 or 72 h later after an acute injection of vehicle, aripiprazole, haloperidol, or quinpirole (a D2 agonist). For comparison purposes, adult rats were pretreated with an 11-day regimen of saline or haloperidol on PD 70-80 and DA synthesis was measured after acute drug treatment on PD 83. Dorsal striatal DA synthesis was determined by measuring L-dihydroxyphenylalanine accumulation after NSD-1015 treatment. In a separate experiment, the ability of repeated drug treatment to up-regulate dorsal striatal D2 receptors was assessed in young and adult rats 72 h after drug discontinuation. The major findings of this study were that: (a) acute treatment with haloperidol and aripiprazole increased DA synthesis while quinpirole reduced it; (b) pretreatment with haloperidol and aripiprazole blunted the synthesis-modulating effects of acutely administered dopaminergic drugs; and (c) DA synthesis of young and adult rats was affected in a qualitatively similar manner by DA agonist, antagonist, and partial agonist drugs. In conclusion, results from the present study suggest that synthesis-modulating autoreceptors in the dorsal striatum are functionally mature by the end of the preweanling period and DA synthesis declines to near basal levels during the course of repeated aripiprazole treatment.

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Effects of dopamine partial-agonist aminoergolines on dopamine metabolism in limbic and extrapyramidal regions of rat brain

Cited by 5 publications

References 9 publications

Postnatal manganese exposure does not alter dopamine autoreceptor sensitivity in adult and adolescent male rats

Postnatal manganese exposure does not alter dopamine autoreceptor sensitivity in adult and adolescent male rats

Effects of aripiprazole and terguride on dopamine synthesis in the dorsal striatum and medial prefrontal cortex of preweanling rats

Effects of repeated and acute aripiprazole or haloperidol treatment on dopamine synthesis in the dorsal striatum of young rats: comparison to adult rats

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