Effects of α-Methyl DOPA and DOPA on the Amphetamine Excitatory Response in Reserpinized Rats

Quinton, R. M.; Halliwell, G.

doi:10.1038/200178a0

Cited by 84 publications

(11 citation statements)

References 3 publications

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“…In 1966, Hanson reported that low doses of ~-methyltyrosine antagonized the actions of amphetamine in reserpinized rats (Quinton and Halliwell, 1963). This observation is confirmed in this study with the finding that 25 mg/kg of ~-methyltyrosine reduced the locomotor stimulation produced by amphetamine in animals previously treated with reserpine ( Fig.…”

Section: E//ect8 O/ O~-methyltyrosine and U14624 On Amphetamine Indsupporting

confidence: 87%

Comparison of tyrosine hydroxylase and dopamine-?-hydroxylase inhibition with the effects of various 6-hydroxydopamine treatments on d-amphetamine induced motor activity

Hollister

Breese

Cooper

1974

Psychopharmacologia

130

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Abstract. The significance of central noradrenergic and dopaminergic neural systems for the locomotor stimulant effects of d-amphetamine were investigated in rats with depletions of norepinephrine, dopamine, or both catecholamines produced by treatment with either reserpine, L-cc-methyl-tyrosine (a-MPT), 6-hydroxydopamine (6-OHDA), or the dopamine-fl-hydroxylase inhibitor 1-phenyl-3-(2-thiazolyl)-2-thiourea (U-14,624). In animals pretreated with reserpine, amphetamine-stimulated locomotor activity was blocked by ~-MPT but not by U-14,624 when amphetamine was given 1 h after these catecholamine synthesis inhibitors. In rats with chronic depletions of brain norepinephrine, dopamine, or both catecholamines produced by different 6-OHDA treatments, both amphetamine-stimulated motor activity and stereotyped behavior were antagonized by treatments reducing dopamine or both catecholamines but not in animals in which brain norepinepbrine was reduced. Results are consistent with the view that the locomotor stimulation and stereotyped behaviors produced by d-amphetamine are dependent upon functional dopaminergic neural systems in brain.

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Section: E//ect8 O/ O~-methyltyrosine and U14624 On Amphetamine Indsupporting

confidence: 87%

Comparison of tyrosine hydroxylase and dopamine-?-hydroxylase inhibition with the effects of various 6-hydroxydopamine treatments on d-amphetamine induced motor activity

Hollister

Breese

Cooper

1974

Psychopharmacologia

130

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“…Similar results have been reported for amphetamine (Weissman, Koe & Tenen, 1966;Hanson, 1966;Dingell, Owens, Norwich & Sulser, 1967;Dominic & Moore, 1969). However, the stereotypy induced by bromocriptine was inhibited in rats pretreated with reserpine, whereas the activity of amphetamine has been reported to be potentiated by this pretreatment (Quinton & Halliwell, 1963;Stolk & Rech, 1968;Dominic & Moore, 1969), and that of apomorphine is not influenced (Ernst, 1967;Maj et al, 1972).…”

Section: Discussionsupporting

confidence: 76%

“…It is well established that administration of apomorphine and (+)-amphetamine to rats leads to the production of stereotyped sniffing, licking and biting behaviour (Quinton & Halliwell, 1963;Ernst, 1967;Randrup & Munkvad, 1968), probably due to the stimulation of dopaminergic mechanisms in the striatum (Ernst & Smelik, 1966;Fog, Randrup & Pakkenberg, 1967). The results reported here show that bromocriptine can also induce such behaviour and it may therefore be tentatively concluded that it too activates dopaminergic mechanisms at this site.…”

Section: Discussionsupporting

confidence: 61%

STIMULANT PROPERTIES OF BROMOCRIPTINE ON CENTRAL DOPAMINE RECEPTORS IN COMPARISON TO APOMORPHINE, (+)‐AMPHETAMINE AND l‐DOPA

Johnson¹,

Loew²,

Vigouret³

1976

British J Pharmacology

210

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I The activity of bromocriptine has been investigated in tests for the stimulation of central dopaminergic mechanisms. The results obtained have been compared with those of apomorphine, (+)-amphetamine and L-DOPA. 2 Bromocriptine (2.5 to 10 mg/kg) induced stereotyped sniffing and licking in rats. The stereotypy was more intense than that induced by L-DOPA and less intense than that of apomorphine and (+)-amphetamine over the dose ranges studied. 3 In rats lesioned unilaterally in the substantia nigra by local injection of 6-hydroxydopamine, bromocriptine, like apomorphine and L-DOPA, induced turning contralateral to the side of the lesion. The smallest dose of bromocriptine to induce turning was 0.5 mg/kg. 4 Reserpine-induced catalepsy in mice was antagonized by bromocriptine, with an ED50 of 1.8 mg/kg. It was intermediate in potency to apomorphine and L-DOPA. 5Spontaneous locomotor activity in mice was stimulated by bromocriptine in a dose-dependent manner from 2.5 to 10 mg/kg after an initial suppression of activity. 6 In all experiments, bromocriptine was characterized by a prolonged duration of activity after a delay in the onset of effect. 7 The stereotyped behaviour induced by bromocriptine was inhibited by prior administration of pimozide, reserpine or a-methyl-p-tyrosine. 8 Bromocriptine-induced turning behaviour was abolished by pretreatment with pimozide, and reduced after a-methyl-p-tyrosine pretreatment. 9 The results obtained support the conclusion that bromocriptine acts by stimulating dopamine receptors in the central nervous system and that intact catecholamine synthesis and granular amine storage mechanisms are necessary for it to bring about its effects.

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“…The prior administration of reserpine enhanced the intensity of the response to (+)-amphetamine but shortened the duration, while pretreatment with a-MT blocked the characteristic excitation induced by the drug. These observations are in agreement with previous findings (Quinton & Halliwell, 1963;Weissman & Koe, 1965).…”

Section: Gross Behaviolural Changes Following the Administration Of Psupporting

confidence: 94%

A study of the role of noradrenaline in behavioural changes produced in the rat by psychotomimetic drugs

Sugrue

1969

British J Pharmacology

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1. LSD-25, psilocybin and JB-329 reduced the noradrenaline content of the rat hypothalamus. 2. All three drugs affected the acquisition of a conditioned avoidance response, LSD-25 and psilocybin retarding and JB-329 enhancing the acquisition. With the exception of JB-329, doses affecting the acquisition of a conditioned avoidance response were lower than those required to decide hypothalamic noradrenaline concentrations. The time of peak drug effect on the acquisition of a conditioned avoidance response occurred approximately 1.5 hr after injection as opposed to 3 hr in the case of noradrenaline content. 3. The amount of LSD-25, psilocybin and JB-329 necessary to elicit gross behavioural excitation was similar to the dose producing noradrenaline depletion. Here also the peak behavioural effect was detected earlier.4. Pretreatment with reserpine and a-MT had no effect on the intensity of gross behavioural excitation induced by LSD-25 and psilocybin but shortened the duration of the response. The excitation induced by JB-329 was abolished by reserpine pretreatment and was markedly reduced both in intensity and duration by the prior injection of a-MT.

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Effects of α-Methyl DOPA and DOPA on the Amphetamine Excitatory Response in Reserpinized Rats

Cited by 84 publications

References 3 publications

Comparison of tyrosine hydroxylase and dopamine-?-hydroxylase inhibition with the effects of various 6-hydroxydopamine treatments on d-amphetamine induced motor activity

Comparison of tyrosine hydroxylase and dopamine-?-hydroxylase inhibition with the effects of various 6-hydroxydopamine treatments on d-amphetamine induced motor activity

STIMULANT PROPERTIES OF BROMOCRIPTINE ON CENTRAL DOPAMINE RECEPTORS IN COMPARISON TO APOMORPHINE, (+)‐AMPHETAMINE AND l‐DOPA

A study of the role of noradrenaline in behavioural changes produced in the rat by psychotomimetic drugs

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