Participation of the medial reticular formation of the medulla oblongata in the supraspinal control of locomotor and postural activities in the guinea pig

Marlinskii, V. V.; Voitenko, L. P.

doi:10.1007/bf01182876

Cited by 7 publications

(8 citation statements)

References 15 publications

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“…For example, continuous stimulation of RS neurons is sufficient for initiation of locomotion in a wide variety of vertebrates: lamprey (Jackson et al, 2007); stingray (Livingston and Leonard, 1990); dogfish (Grillner and Wallén, 1984); fish (Uematsu and Todo, 1997); birds (Steeves et al, 1987); and mammals (Ross and Sinnamon, 1984; Garcia-Rill and Skinner, 1987). In addition, in some vertebrates, RS neurons also have been shown to be necessary for initiation of locomotion (Shefchyk et al, 1984; Bernau et al, 1991; Marlinski and Voitenko, 1992; Paggett et al, 2004). …”

Section: Introductionmentioning

confidence: 99%

Cyclic AMP stimulates neurite outgrowth of lamprey reticulospinal neurons without substantially altering their biophysical properties

2013

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Reticulospinal (RS) neurons are critical for initiation of locomotor behavior, and following spinal cord injury (SCI) in the lamprey, the axons of these neurons regenerate and restore locomotor behavior within a few weeks. For lamprey RS neurons in culture, experimental induction of calcium influx, either in the growth cone or cell body, is inhibitory for neurite outgrowth. Following SCI, these neurons partially downregulate calcium channel expression, which would be expected to reduce calcium influx and possibly provide supportive conditions for axonal regeneration. In the present study, it was tested whether activation of second messenger signaling pathways stimulates neurite outgrowth of lamprey RS neurons without altering their electrical properties (e.g. spike broadening) so as to possibly increase calcium influx and compromise axonal growth. First, activation of cAMP pathways with forskolin or dbcAMP stimulated neurite outgrowth of RS neurons in culture in a PKA-dependent manner, while activation of cGMP signaling pathways with dbcGMP inhibited outgrowth. Second, neurophysiological recordings from uninjured RS neurons in isolated lamprey brain-spinal cord preparations indicated that dbcAMP or dbcGMP did not significantly affect any of the measured electrical properties. In contrast, for uninjured RS neurons, forskolin increased action potential duration, which might have increased calcium influx, but did not significantly affect most other electrical properties. Importantly, for injured RS neurons during the period of axonal regeneration, forskolin did not significantly alter their electrical properties. Taken together, these results suggest that activation of cAMP signaling by dbcAMP stimulates neurite outgrowth, but does not alter the electrical properties of lamprey RS neurons in such a way that would be expected to induce calcium influx. In conclusion, our results suggest that activation of cAMP pathways alone, without compensation for possible deleterious effects on electrical properties, is an effective approach for stimulating axonal regeneration of RS neuron following SCI.

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Section: Introductionmentioning

confidence: 99%

Cyclic AMP stimulates neurite outgrowth of lamprey reticulospinal neurons without substantially altering their biophysical properties

2013

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“…The rubrospinal tract influences movement through direct and reciprocal spinal motor projections that reflect activity of the rubro-cortico-cerebellar premotor pathway Miller and Houk, 1995). The vestibulospinal and reticulospinal tracts affect postural control and balance during locomotion, providing afferent input to premotoneuronal interneurons and ultimately influencing converging and diverse descending motor inputs and the spinal locomotor pattern generator (Dubuc, 1992;Fetcho, 1992;Marlinsky and Voitenko, 1992;Marlinsky, 1992;Perreault et al, 1993;Vinay and Grillner, 1993;Akbarian et al, 1994;Bussieres and Iwakiri et al, 1995;Grillner et al, 1995;Gossard et al, 1996;Pflieger and Cabana, 1996). Specialization in the vestibular system in particular has been important for the evolution of bipedal locomotion in humans (Spoor et al, 1994).…”

Section: Abstract: Corticospinal; Neurotrophin-3 (Nt-3); Spinal Cordmentioning

confidence: 99%

Cellular Delivery of Neurotrophin-3 Promotes Corticospinal Axonal Growth and Partial Functional Recovery after Spinal Cord Injury

et al. 1997

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The injured adult mammalian spinal cord shows little spontaneous recovery after injury. In the present study, the contribution of projections in the dorsal half of the spinal cord to functional loss after adult spinal cord injury was examined, together with the effects of transgenic cellular delivery of neurotrophin-3 (NT-3) on morphological and functional disturbances. Adult rats underwent bilateral dorsal column spinal cord lesions that remove the dorsal corticospinal projections or underwent more extensive resections of the entire dorsal spinal cord bilaterally that remove corticospinal, rubrospinal, and cerulospinal projections. Long-lasting functional deficits were observed on a motor grid task requiring detailed integration of sensorimotor skills, but only in animals with dorsal hemisection lesions as opposed to dorsal column lesions. Syngenic primary rat fibroblasts genetically modified to produce NT-3 were then grafted to acute spinal cord dorsal hemisection lesion cavities. Up to 3 months later, significant partial functional recovery occurred in NT-3-grafted animals together with a significant increase in corticospinal axon growth at and distal to the injury site. These findings indicate that (1) several spinal pathways contribute to loss of motor function after spinal cord injury, (2) NT-3 is a neurotrophic factor for the injured corticospinal projection, and (3) functional deficits are partially ameliorated by local cellular delivery of NT-3. Lesions of the corticospinal projection may be necessary, but insufficient in isolation, to cause sensorimotor dysfunction after spinal cord injury in the rat.

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“…Inactivation of NGC/NMC by cooling, chemical injection, and lesion either blocked stepping induced by mesencephalic locomotion region stimulation, or increased the threshold for mesencephalic locomotion region stimulation to induce locomotion [290,347,423]. Our study showed that microinjection of glutamate antagonists into the NMC reversed muscle tone suppression induced by pontine carbachol injection [244].…”

Section: Motor Activitymentioning

confidence: 63%

Sensory-Motor Integration in the Medial Medulla

Lai¹,

Siegel²

2005

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The rostromedial medulla, including the nucleus gigantocellularis (NGC) and magnocellularis (NMC), plays a role as a relay nucleus for both the sensory and motor systems. The NGC/NMC is important in the modulation of somatic and visceral activities. Electrophysiological and pharmacological studies have shown that the NGC/NMC is involved in nociception, locomotion, regulation of basal muscle tone, sleep, as well as cardiovascular and pulmonary activities. Pharmacological and electrical stimulation of the NGC/NMC can produce opposite effects on physiological functions: analgesia or hyperalgesia, and suppression or facilitation of motor activity, depending on the subgroups of neurons activated and the states of the sleep-wake cycle at the time of stimulation. Sensory inputs including noxious and innocuous stimuli converge on the NGC/NMC. The NGC/NMC also plays a role as a relay nucleus, which sends sensory information to the higher centers. The NGC/NMC receives projections from the supra-bulbar motor facilitatory and inhibitory areas, and plays an important role in the regulation of motor activity. Pharmacologically, neurons in the NGC/NMC contribute to opioid, glutamate, GABA, acetylcholine, dopamine, substance P, neurotensin, hypocretin (orexin), and cannabinoid mediated sensory and motor activities, as well as cardiovascular and pulmonary functions. In this review, we will discuss the neuronal morphology, physiological functions and pharmacological characterization of the rostromedial medulla. We will consider the evidence that dysfunction of the NGC/NMC is a factor in a number of neurological diseases, including Parkinson's disease, restless legs syndrome, periodic leg movement, REM sleep behavior disorder, amyotrophic lateral sclerosis and narcolepsy. INTRODUNTIONThe medullary reticular formation is traditionally segregated into the medial somatic-and lateral visceralrelated areas. However, somatic and autonomic activities are well coordinated. For example, cardiovascular-respiratory changes are correlated with somatic sensory-motor activity during exercise. Coordination of somatic and autonomic activity can result from interconnections between somatic and autonomic control structures, as well as interactions within nuclei, which are involved in both somatic and autonomic activities. The rostromedial medulla (RMM) is one of the areas of the central nervous system (CNS) that is involved in both somatic and autonomic regulation. However, the RMM has traditionally been considered as a somatic nociceptive and a motor control area. The autonomic role of the RMM has received little attention, although Bach [22] demonstrated that the activation of RMM causes changes in cardiovascular and respiratory activity, as well as the facilitation and inhibition of somatic motor activity in 1952. Therefore, we will discuss the functional aspects of RMM in the modulation of both somatic and autonomic systems in this review. Section 1 will focus on the morphology of the RMM, and the anatomical link between RMM and the other areas...

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Participation of the medial reticular formation of the medulla oblongata in the supraspinal control of locomotor and postural activities in the guinea pig

Cited by 7 publications

References 15 publications

Cyclic AMP stimulates neurite outgrowth of lamprey reticulospinal neurons without substantially altering their biophysical properties

Cyclic AMP stimulates neurite outgrowth of lamprey reticulospinal neurons without substantially altering their biophysical properties

Cellular Delivery of Neurotrophin-3 Promotes Corticospinal Axonal Growth and Partial Functional Recovery after Spinal Cord Injury

Sensory-Motor Integration in the Medial Medulla

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