snx-230 and Disease-Models--Animal

Excessive accumulation of intracellular calcium is the most critical step after spinal cord injury (SCI). Reducing the calcium influx should result in a better recovery from SCI. Calcium channel blockers have been shown a great potential in reducing brain and spinal cord injury. In this study, we first tested the neuroprotective effect of MVIIC on slices of spinal cord subjected to ischemia evaluating cell death and caspase-3 activation. Thereafter, we evaluated the efficacy of MVIIC in ameliorating damage following SCI in rats, for the first time in vivo. The spinal cord slices subjected a pretreatment with MVIIC showed a cell protection with a reduction of dead cells in 24.34% and of caspase-3-specific protease activation. In the in vivo experiment, Wistar rats were subjected to extradural compression of the spinal cord at the T12 vertebral level using a weigh of 70 g/cm, following intralesional treatment with either placebo or MVIIC in different doses (15, 30 and 60 pmol) five minutes after injury. Behavioral testing of hindlimb function was done using the Basso Beattie Bresnahan locomotor rating scale, and revealed significant recovery with 15 pmol (G15) compared to other trauma groups. Also, histological bladder structural revealed significant outcome in G15, with no morphological alterations, and anti-NeuN and TUNEL staining showed that G15 provided neuron preservation and indicated that this group had fewer neuron cell death, similar to sham. These results showed the neuroprotective effects of MVIIC in in vitro and in vivo model of SCI with neuronal integrity, bladder and behavioral improvements.

Topics: Animals; Apoptosis; Disease Models, Animal; In Situ Nick-End Labeling; In Vitro Techniques; Male; Neurons; Neuroprotective Agents; omega-Conotoxins; Rats; Rats, Wistar; Real-Time Polymerase Chain Reaction; Recovery of Function; Spinal Cord Injuries

This study investigated the behavioural and anticonvulsant effects of voltage-sensitive calcium channel blockers in DBA/2 mice. Omega-Conotoxin MVIIC (0.1, 0.3 micrograms ICV/mouse) and omega-agatoxin IVA (0.1, 0.3, 1 micrograms ICV), which act predominantly at P- and/or Q-type calcium channels, prevented clonic and tonic sound-induced seizures in this animal model of reflex epilepsy (ED50 values with 95% confidence limits for protection against clonic sound-induced seizures were 0.09 (0.04-0.36) micrograms ICV and 0.09 (0.05-0.15) micrograms ICV respectively and against tonic seizures 0.07 (0.03-0.16) micrograms ICV and 0.08 (0.04-0.13) micrograms ICV, respectively). The N-type calcium channel antagonists omega-conotoxin GVIA and omega-conotoxin MVIIA were also tested in this model. Omega-Conotoxin GVIA was anticonvulsant in DBA/2 mice, but only at high doses (3 micrograms ICV prevented tonic seizures in 60% of the animals; 10 micrograms ICV prevented clonic seizures in 60% and tonic seizures in 90% of the animals), whereas omega-conotoxin MVIIA did not inhibit sound-induced seizures in doses up to 10 micrograms ICV. Both omega-conotoxin GVIA and omega-conotoxin MVIIA induced an intense shaking syndrome in doses as low as 0.1 microgram ICV, whereas omega-conotoxin MVIIC and omega-agatoxin IVA did not produce shaking at any of the doses examined. Finally, omega-conotoxin GI (0.01-1 microgram ICV) and alpha-conotoxin SI (0.3-30 micrograms ICV), which both act at acetylcholine nicotinic receptors, were not anticonvulsant and did not induce shaking in DBA/2 mice. These results confirm that blockers of N- and P-/Q-type calcium channels produce different behavioural responses in animals. The anticonvulsant effects of omega-conotoxin MVIIC and omega-agatoxin IVA in DBA/2 mice are consistent with reports that P- and/or Q-type calcium channel blockers inhibit the release of excitatory amino acids and are worthy of further exploration.

Topics: Acoustic Stimulation; Animals; Behavior, Animal; Calcium Channel Blockers; Disease Models, Animal; Male; Mice; Mice, Inbred DBA; omega-Agatoxin IVA; omega-Conotoxin GVIA; omega-Conotoxins; Peptides; Seizures; Spider Venoms