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  • 1990-1994  (2)
  • 1980-1984
  • Conditioned reinforcement  (1)
  • Graft  (1)
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  • 1990-1994  (2)
  • 1980-1984
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Keywords
  • 1
    ISSN: 1432-1106
    Keywords: MPTP ; Graft ; Behavior ; Parkinson's disease ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fetal substantia nigra (SN) cells were transplanted into the caudate nucleus (CN) of four vervet monkeys (Cercopithecus aethiops sabaeus) that had been treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). MPTP treatment appears to produce a syndrome similar to that observed in patients with idiopathic Parkinson's disease. Normal and parkinsonian behaviors were quantitated by trained observers 5 days/week. Twenty-eight behaviors based on previous factor analyses were individually scored and rated. Parkinsonian signs included freezing, head and limb tremor, difficulty in eating, delayed initiation of movement, poverty of movement, tremor that stopped with intention, decreased response to threats, and lying immobile in the cage. These signs were combined to give an overall rating of parkinsonism. A summary measure of ‘normal’ healthy behavior was also examined, including such behaviors as yawning, scratching, self-grooming, shifting, and eating. Overall ratings of parkinsonism increased and those of healthy behavior decreased after MPTP. In the 4 monkeys grafted with fetal SN cells into the CN, behavior returned to pre-treatment levels by the time of sacrifice (2, 5, or 7.5 months after grafting). Three control subjects were transplanted with either SN cells into an inappropriate brain site (cortex) or inappropriate, non-dopaminergic, cells (cerebellar) into the CN. Subjects were also compared with three control animals that did not receive MPTP but received cryopreserved or fresh SN and other cells into the CN. Only MPTP-treated subjects that received SN cells into the CN showed evidence of a reversal of the MPTP syndrome after transplantation. In addition, grafting in animals that were not MPTP-treated did not appear to affect behavior. This paper reports the specific behavioral effects of severe MPTP toxicity that were or were not reversed after transplantation and suggests that only fetal SN cells grafted into the CN may be able to reverse behavioral deficits in MPTP-treated monkeys.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2072
    Keywords: Conditioned reinforcement ; Dopamine ; Noradrenaline ; d-Amphetamine ; Dorsal noradrenergic bundle ; Nucleus accumbens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Three experiments examined the behavioural, pharmacological and neural specificity of the previously reported potentiation of responding with conditioned reinforcement following intra-accumbensd-amphetamine, by studying the effects of intraaccumbens dopamine (DA) and noradrenaline, using an acquisition of a new response procedure. In experiment 1, the effects of intra-cerebral DA infusions (5, 20, 50 µg/2 µl) were compared in four conditions: (i) intra-accumbens DA following positive pairing of the conditioned stimulus (CS) and water during training; (ii) as (i) but also following a systemic dose of the DA receptor antagonist alpha-flupenthixol; (iii) intra-accumbens DA following random pairing of the CS and water during training; and (iv) as (i) but with intra-caudate rather than intra-accumbens DA. The results showed that only with intra-accumbens DA in the positive pairing condition was there a significant dose-dependent increase in responding. In experiment 2, the effects of a higher range of doses (20, 100, 200 µg) and smaller infusion volume (5, 25, 50 µg/l µl) of intra-accumbens DA were studied, in comparison with a similar range of doses (5, 25, 50 µg/l µl) of intra-accumbens noradrenaline (NA). Only DA produced a selective, dose-dependent increase in responding with conditioned reinforcement. In experiment 3 neurotoxic lesions of the dorsal noradrenergic bundle (DNAB) using 6-hydroxydopamine producing profound (about 90%) depletion of cortical and nucleus accumbens NA levels had no effect on the increased responding with conditioned reinforcement produced by intra-accumbensd-amphetamine (3, 10, 30 µg/l µl). The results are discussed in terms of the neurochemical mediation of the potentiation of the effects of conditioned reinforcers byd-amphetamine and the role of DA-dependent mechanisms of the nucleus accumbens in reward-related processes.
    Type of Medium: Electronic Resource
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