Cord Of Neonatal Rat Research Articles

Transplantation of adult spinal cord grafts into spinal cord transected rats improves their locomotor function.

Grafted embryonic central neural tissue pieces can recover function of hemisected spinal cord in neonatal rats and promote axonal growth in adults. However, spinal cord segments from adults have not been used as donor segments for allogeneic transplantation. Here, we utilized adult spinal cord tissue grafts (aSCGs) as donor constructs for repairing complete spinal cord injury (SCI). Moreover, to provide a favourable microenvironment for SCI treatment, a growth factor cocktail containing three growth factors (brain-derived neurotrophic factor, neurotrophin-3 and vascular endothelial growth factor), was applied to the aSCG transplants. We found that the locomotor function was significantly improved 12 weeks after transplantation of aSCGs into the spinal cord lesion site in adult rats. Transplantation of aSCGs combined with these growth factors enhanced neuron and oligodendrocyte survival and functional restoration. These encouraging results indicate that treatment of complete SCI by transplanting aSCGs, especially in the presence of growth factors, has a positive effect on motor functional recovery, and therefore could be considered as a possible therapeutic strategy for SCI.

Effects of electrical stimulation of sciatic nerve on synaptic plasticity of spinal dorsal horn, hippocampal CA1 region and spinal c-fos, hippocampal CA1 region expression in neonatal rats

To explore the response to nociceptive stimuli in spinal cord of neonatal rat and observe the electrical stimulation of sciatic nerve on synaptic plasticity of spinal dorsal horn, hippocampal CA1 region and spinal c-fos, hippocampal CA1 region expression in neonatal rats. The rats were divided into neonatal and adult groups. The evoked potentials of left spinal dorsal horn from T13-L1 and right hippocampal CA1 region were recorded. After conditional electric stimulations, the potential amplitudes were recorded. When the incubation period reached 120 min, D-AP5 was added to spinal cord of rats and resulting changes in field potential and c-fos expression were recorded. Long-term potentiation (LTP) in neonatal rats was mainly evoked by A-type nerve fibers whereas LTP in adult rats was mainly evoked by C-type nerve fibers. C-fos expression was significantly increased in superficial, deep layers of spinal dorsal horn, ventral horn and hippocampal CA1 region in neonatal rats. Pain signals change with age.

Synaptic targets of commissural interneurons in the lumbar spinal cord of neonatal rats.

There is strong evidence that commissural interneurons, neurons with axons that extend to the contralateral side of the spinal cord, play an important role in the coordination of left/right alternation during locomotion. In this study we investigated the projections of commissural interneurons to motor neurons and other commissural interneurons on the other side of the spinal cord in neonatal rats. To establish whether there are direct contacts between axons of commissural interneurons and motor neurons, we carried out two series of experiments. In the first experiment we injected biotinylated dextran amine (BDA) into the lateral motor column to retrogradely label commissural interneurons that may have direct projections to motor neurons. Stained neurons were recovered in the ventromedial areas of the contralateral gray matter in substantial numbers. In the second experiment BDA was injected into the ventromedial gray matter on one side of the lumbar spinal cord, whereas motor neurons were simultaneously labeled on the opposite side by applying biocytin onto the ventral roots. BDA injections into the ventromedial gray matter labeled a strong axon bundle that arose from the site of injection, crossed the midline in the ventral commissure, and extensively arborized in the contralateral ventral gray matter. Many of these axons made close appositions with dendrites and somata of motor neurons and also with commissural interneurons retrogradely labeled with BDA. The results suggest that commissural interneurons may establish monosynaptic contacts with motor neurons on the opposite side of the spinal cord. Our findings also indicate that direct reciprocal connections between commissural interneurons on the two sides of the spinal cord may also exist.

Involvement of membrane-bound peptidases in the inactivation of opioid peptide neurotransmitters in the isolated spinal cord of neonatal rat

Involvement of membrane-bound peptidases in the inactivation of opioid peptide neurotransmitters in the isolated spinal cord of neonatal rat

Replacement of the spinal cord in neonatal rats by embryonic homotopic structures

Replacement of the spinal cord in neonatal rats by embryonic homotopic structures

Does L-dopa depolarize motoneurons in the isoalted spinal cord of neonatal rat?

Does L-dopa depolarize motoneurons in the isoalted spinal cord of neonatal rat?

Differential Distribution of Immunoreactive Angiotensinogen in the Hind-Brain and Spinal Cord of Neonatal and Adult Rats

The present communication deals with the cytochemical localization of angiotensinogen (ATG) immunoactivity in the hind-brain and spinal cord of neonatal (1-day-old) and adult (3-month-old pregnant) female rats. In the neonatal hind-brain, the immunoreactive cells were more numerous than in that of adult rats. In the adult rat hind-brain, the number of ATG-positive cells was quite limited in each nucleus. Further, in some nuclei, only neurons or neuroglia were positive, while in others the immunoactivity was observed in both the components. Spinal cords of neonatal rats showed a few undifferentiated ATG-positive cells in the grey matter. Contrary to this, the spinal cord of adult animals contained numerous immunoreactive glial cells in the grey matter, fasciculus cuneatus and fasciculus gracilis. Immunoactivity in the neurons was localized in the Nissl bodies.

Effect of magnesium on depression of the monosynaptic reflex induced by 2-chloroadenosine or hypoxia in the isolated spinal cord of neonatal rats

Superfusion of the isolated spinal cord of neonatal rats (4-9 days postpartum) with physiological medium containing 2-chloroadenosine (2-CA) or anoxic medium (equilibrated with 95% N2-5% CO2) depressed the evoked monosynaptic reflex (MSR) recorded extracellularly from a ventral spinal root. The effectiveness of 2-CA or anoxic medium in depressing the MSR was significantly reduced when the concentration of Mg2+ in the physiological medium was lowered from 1.25 X 10(-3) M to zero. The absence of Mg2+ resulted in a 7-fold shift to the right of the concentration-response curve to 2-CA and a reduction in the maximal depression of the MSR from 100% to 65 +/- 4% (mean +/- S.E.M.) of control. A 10 min exposure to anoxic medium containing 1.25 X 10(-3) M Mg2+ decreased the amplitude of the MSR to 23 +/- 6% of control, whilst in zero Mg2+ a decrease to only 50 +/- 5% of control was observed. These data provide further evidence that the response to adenosine, at the A1-receptor, is sensitive to Mg2+ ion concentration and suggest that there is an absolute requirement for Mg2+ in order to obtain full expression of the adenosine effect. Furthermore, the data are consistent with the hypothesis that adenosine is an important mediator of hypoxia-induced depression of the evoked MSR in the spinal cord, and suggest a potential role for Mg2+ during or after exposure to hypoxia in altering the actions of adenosine on neuronal activity or synaptic events.

Reversal of Organophosphorus-induced Depression of the Monosynaptic Reflex in Spinal Cords of Neonatal Rats by Thyrotropin-Releasing Hormone

Reversal of Organophosphorus-induced Depression of the Monosynaptic Reflex in Spinal Cords of Neonatal Rats by Thyrotropin-Releasing Hormone

Thyrotropin-Releasing Hormone Reverses Phencyclidine- and Ketamine-induced Depression of the Monosynaptic Reflex in the Spinal Cord of Neonatal Rats

Thyrotropin-Releasing Hormone Reverses Phencyclidine- and Ketamine-induced Depression of the Monosynaptic Reflex in the Spinal Cord of Neonatal Rats

Thyrotropin-Releasing Hormone Reverses Phencyclidine- and Ketamine-induced Depression of the Monosynaptic Reflex in the Spinal Cord of Neonatal Rats

Thyrotropin-Releasing Hormone Reverses Phencyclidine- and Ketamine-induced Depression of the Monosynaptic Reflex in the Spinal Cord of Neonatal Rats

Reversal of Organophosphorus-induced Depression of the Monosynaptic Reflex in Spinal Cords of Neonatal Rats by Thyrotropin-Releasing Hormone

Reversal of Organophosphorus-induced Depression of the Monosynaptic Reflex in Spinal Cords of Neonatal Rats by Thyrotropin-Releasing Hormone