摘要:

AbstractThe ascending monoamine pathways in the rat brain are demonstrated by the pile up of fluorescent material occurring in the axons after various types of lesions. The anatomy of the pathways is outlined in drawings of frontal sections of the brain and the origin and termination of several pathways is determined by studying the anterograde and retrograde degeneration occurring after well localised lesions. It is possible to separate the ascending NA pathways into a dorsal and a ventral bundle of axons. The dorsal bundle innervates the cortex and the hippocampus and the ventral bundle supplies NA nerve terminals to the medulla, the pons, the mesencephalon and the diencephalon. The dorsal bundle is found to originate in the locus coeruleus. Lesions of this nucleus abolish the nerve terminals in all cortical areas and in several other areas of the brain indicating a unique role for the locus coeruleus in influencing the activity of the entire brain. The 5‐HT pathways have a distribution similar to the ventral NA pathyway. The course of the nigro‐striatal and the meso‐limbic DA pathways is presented in d

ISSN:0001-6772    

DOI:10.1111/j.1365-201X.1971.tb10998.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractAmphetamine induced vigorous rotational behaviour in rats where the nigrostriatal dopamine (DA) system was unilaterally degenerated by an intracerebral injection of 6‐hydroxydopamine (6‐OH‐DA). The rotational behaviour was analysed in a specially designed “rotometer” and found highly reproducable. The intensity of the rotation was proportional to the extent of degeneration in the DA system. The amphetamine site of action was in all probability presynaptic as amphetamine caused a rotation in the opposite direction as compared to the DA receptor stimulating drug apomorphine. Tyrosine hydroxylase inhibition abolished the amphetamine effect, while reserpine potentiated the effect. Evidence was also obtained that the amphetamine induced release of DA was dependent upon nerve impulses. The rotational behaviour reflected the degree of DA receptor stimulation, but changes in the noradrenaline (NA) transmission seemed to modulate the behaviour. Decreased NA transmission after dopamine‐β‐hydroxylase inhibition increased the rotational behaviour. The unilateral degeneration of the DA system was studied by the changes in posture and movements that occurred during the degeneration. After inhibition of the monoamine oxidase the rats showed a strong rotation beginning on the 23d and ending on the 33d hour after the operation. The rotational behaviour was probably due to degeneration release of DA and equivalent to the degeneration contraction of the nictitating membrane in the peripheral nervous system Amphetamine greatly potentiated the spontaneous degeneration release duri

ISSN:0001-6772    

DOI:10.1111/j.1365-201X.1971.tb10999.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe effect of L‐DOPA and the dopamine (DA) receptor stimulating drug apomorphine was studied in rats after unilateral degeneration of the nigrostriatal DA system by intracerebral injection of 6‐hydroxydopamine. Both apomorphine and L‐DOPA induced a strong rotational behaviour which was registered in a specially designed “rotameter”. The direction of the rotation indicated that the denervated striatum was more sensitive to DA receptor stimulating drugs than the innervated striatum. This supersensitivity probably corresponded to the decentralisation type of supersensitivity in the peripheral nervous system although it developed faster. The action of L‐DOPA was inhibited by pretreatment with the DOPA‐decarboxylase inhibitor Ro4–4602 which indicated that L‐DOPA must be converted to DA in order to stimulate the supersensitive postsynaptic cells. Pretreatment with a single dose of reserpine also induced supersentitivity to apomorphine which reached its maximum on the 3rd day and then decreased on the 4th day. Postsynaptic supersensitivity after degeneration of the nigro‐striatal DA system is probably an important reason for the effectiveness of the L‐DOPA therapy agains

ISSN:0001-6772    

DOI:10.1111/j.1365-201X.1971.tb11000.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe functional role of the nigro‐striatal dopamine (DA) system has been investigated on the basis of a recent detailed mapping of its path and a new method of lesioning the catecholamine systems selectively by intracerebral injection of 6‐hydroxydopamine (6‐OH‐DA). The investigation was especially focused on the symptoms of adipsia, aphagia, hypokinesia and catalepsia after lateral hypothalamic lesions as such lesions may interrupt the ascending DA axons. Electrocoagulations or 6‐OH‐DA lesions were performed bilaterally at several sites along the DA pathway and the behavioural effects were evaluated in relation to the histochemically detected lesion of the DA pathway. It was concluded that bilateral complete degeneration of the nigro‐striatal DA pathway produces severe, long lasting adipsia and aphagia, hypoactivity, difficulties to initiate activity and loss of exploratory behaviour and curiosity. Experiments with DA receptor stimulating and blocking drugs supported the lesion results. Catalepsia and somnolence were attributed to the interruption of other pathways. The results suggest an important role for the nigro‐striatal DA system and the striatum in the control of behaviour. A number of symptoms earlier related to the hypothalamus may in fact be due to disturbance of the nigro‐s

ISSN:0001-6772    

DOI:10.1111/j.1365-201X.1971.tb11001.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY