Effects of spinal transection in neonatal and weanling rats: Survival of function

Stelzner, Dennis J.; Ershler, W. B.; Weber, Eric

doi:10.1016/0014-4886(75)90039-4

Cited by 154 publications

(67 citation statements)

References 23 publications

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“…The sequence of developmental events was similar to that of Wistar rats as de scribed by Salas and Schapiro [30] but the CFY rats used in the present study exhibited a somewhat advanced maturational level dur ing the first postnatal week. Our findings on the developmental patterns of motor coordi nation are consistent with anatomical studies that report very few supraspinal connections with the lumbosacral cord perinatally, where as 7 days after birth there was a behaviorally significant increase in this type of synapse [11,32,33], In relation to their effects on swimming be havior, the drugs used in this study can be di vided into two groups: (1) substances known to influence dopaminergic mechanisms al tered the developmental pattern of motor coordination and also changed FS and LTS, and (2) substances known to primarily affect the serotonergic system failed to influence motor coordination, although they altered FS and LTS. L-dopa induced facilitation of swimming behavior within 30 min of injec tion.…”

Section: Discussionsupporting

confidence: 78%

The Role of Dopaminergic and Serotonergic Mechanisms in the Development of Swimming Ability of Young Rats

1981

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Neonatal swimming behavior was studied after a single subcutaneous injection of L-dopa methyl ester (50 mg/kg; 200 mg/kg) apomorphine (0.1 mg/kg; 1.0. mg/kg), DL-amphetamine (0.5 mg/kg; 10 mg/kg), haloperidol (0.5 mg/kg; 1.0 mg/kg), L-tryptophan (50 mg/kg; 100 mg/kg), methysergide (1.0 mg/kg; 5.0 mg/kg) as well as intraventricular injection of 100 µg 6-OHDA. 1-, 3-, 5- and 7-day-old rats were placed into a temperature-controlled aquarium (37°C) and the pattern of motor coordination, latency time to swimming (LTS) and the number of foreleg strokes for 10 s (FS) were measured. When compared to the physiological saline-injected controls, rats that received L-dopa showed a striking increase of FS at all ages but the most striking improvement of motor coordination was found in newborn rats. On day 1 both doses of DL-amphetamine induced increases in FS and improvement of motor coordination, whereas apomorphine failed to show any effect at this age. On days 3, 5 and 7 low doses of DL-amphetamine and apomorphine increased the FS. However, high doses resulted in a decrement in swimming performance. Haloperidol impaired swimming on day 1 but produced a significant increase of FS on days 5 and 7. Neonatal injection of 6-OHDA delayed development of motor coordination, reduced FS and increased LTS. On days 3,5 and 7 high doses of L-tryptophan elicited an increase of FS, while high doses of methysergide caused significant impairment of performance. It is suggested that the brain rapidly converts the administered L-dopa to dopamine during the first week of life and there appears to be a strong dependent relationship between the pattern of motor coordination and the amount of available dopamine in the developing brain.

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Section: Discussionsupporting

confidence: 78%

The Role of Dopaminergic and Serotonergic Mechanisms in the Development of Swimming Ability of Young Rats

1981

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“…All of the above-mentioned investigators described that the critical period for initiation of spinal walking came at about 2 weeks after birth. Possible explanations are, as described by Stelzner et al (1975Stelzner et al ( , 1979, that development of local circuitry in the transected cord before functional supraspinal connections have formed and facilitation produced by an increased number of dorsal root afferents after transection plays an important role for the behavioral recovery of neonatal spinal animals.…”

Section: Discussionmentioning

confidence: 99%

“…Stelzner et al 1975;Goldberger and Murray 1978;Cotman 1983). Although kinematic development of spinal locomotion is much slower in adult spinal dogs than in neonatal spinal animals, the developmental process, including the sequence of emergence of reflexes, is almost the same in both spinal animals.…”

Section: Discussionmentioning

confidence: 99%

Functional recovery of locomotive behavior in the adult spinal dog.

Handa

Naito

Watanabe

et al. 1986

Tohoku J. Exp. Med.

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Complete transection of the midthoracic spinal cord was performed on adult female dogs. Development of reflexes and locomotive movements in the hindlimbs after spinal transection was investigated over several months. In the earlier stages after the surgery, dogs showed flaccid paralysis of the hindlimbs. Within several weeks, muscle tone of the hindlimbs was gradually increased accompanied by development of flexion reflex with after-discharge in addition to monosynaptic reflexes. Alternating stepping movement also began to develop. Afterward, extensor thrust and crossed extension reflex were observed. Standing behavior of the hindlimbs was found after enough development of the extensor thrust and correct placement of the pads of the toes. Steady development of stepping and standing caused forward locomotion using fore-and hindlimbs. This walking behavior of the hindlimbs was never inhibited by additional spinal cord transection. These findings indicate that the isolated spinal cord caudal to the transected site is responsible for the locomotive behavior of the hindlimbs in adult spinal dogs. Spinal automatism and development of responses induced by afferent inflow from outside the cord may help to explain such functional recovery of the paralyzed hindlimbs.

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“…For example, a number of neonatal organs (e.g., heart, adrenal medulla), in contrast to these organs in adults, function without direct neural connectivity (e.g., Seidler & Slotkin, 1986;Tucker, 1985). In addition, the neonatal spinal cord is capable of exhibiting many motor functions independent of descending influences, as indicated by spinal transection (Stelzner, Ershler, & Weber, 1975). Moreover, the transection procedure itself does not produce spinal shock as it does in older animals (Stelzner, 1982), again suggesting that the neonatal nervous system is more, not less, tolerant of insult and injury than the adult nervous system.…”

Section: Do Current Functional Hypotheses Fit the Developmental Data?mentioning

confidence: 98%

A developmental and component analysis of active sleep

Blumberg

Lucas

1996

Dev. Psychobiol.

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Effects of spinal transection in neonatal and weanling rats: Survival of function

Cited by 154 publications

References 23 publications

The Role of Dopaminergic and Serotonergic Mechanisms in the Development of Swimming Ability of Young Rats

The Role of Dopaminergic and Serotonergic Mechanisms in the Development of Swimming Ability of Young Rats

Functional recovery of locomotive behavior in the adult spinal dog.

A developmental and component analysis of active sleep

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