Reversible inactivation and excitation of nucleus raphe magnus can modulate tail blood flow of male wistar rats in response to hypothermia

The nucleus raphe magnus [NRM] is involved in thermoregulatory processing. There is a correlation between changes in the firing rates of the cells in the NRM and the application of the peripheral thermal stimulus. We examined the effect of reversible inactivation and excitation of NRM on mechanisms involved in tail blood flow [TBF] regulation in hypothermia. Hypothermia was induced in Male Wistar rats and cannula was implanted above the NRM. To evaluate the effect of nucleus inactivation on TBF, the amount of TBF was measured by Laser Doppler in hypothermic rats, before and after lidocaine microinjection into NRM. TBF was also measured after glutamate microinjection to assess the effect of nucleus excitation in hypothermic rats. Results indicated that after dropping TBF by hypothermia, microinjection of lidocaine into NRM significantly decreased TBF from 54.43 +/- 5.7 to 46.81 +/- 3.4, whereas glutamate microinjection caused a significant increase from 44.194 +/- 0.6 to 98 +/- 10.0 Conclusion: These data suggest that NRM have thermoregulatory effect in response to hypothermia

study of glutamate transporter 3 [EAAT3] expression, serum TNF-alpha level, and NF-KB activity in ischemic tolerance induced by prolonged and intermittent normobaric hyperoxia

Recent studies suggest that intermittent and prolonged normobaric hyperoxia [HO] results in ischemic tolerance to preventing ischemia brain injury. In this research attempts were made to see the changes in excitatory amino-acid transporter 3 [EAAT3], TNF- alpha levels, and NF- kappa B activity following prolonged and intermittent NBHO preconditioning. Rats were divided into four experimental groups, each with 21 animals. The first two groups were exposed to 95% inspired HO for 4h/day for 6 consecutive days [intermittent HO; InHO] or for 24 continuous hours [prolonged HO; PrHO]. The second two groups acted as controls, and were exposed to 21% oxygen in the same chamber [nomobaric normoxia, RA; room air] continuously for six days [intermittent RA, InRA] or for 24 hours [prolonged RA; PrRA]. Each main group was subdivided to MCAO- operated [middle cerebral artery occlusion], sham-operated [without MCAO], and intact [without any surgery] subgroups. After 24 h, MCAO-operated subgroups were subjected to 60min of right MCAO. After 24h reperfusion, neurologic deficit score [NDS] were assessed in MCAO-operated subgroups. Immediately and 48 h after pretreatment, blood sampling for assessment of serum TNF- alpha levels were performed. Then, the effect of InHO and PrHO on serum TNF - alpha levels, NF - kappa B activity and EAAT3 expression were measured. Reconditioning with InHO and PrHO decreased NDS and upregulate EAAT3 and increase serum TNF- alpha level and NF- kappa B activity significantly. Although further studies are needed to clarify the mechanisms of ischemic tolerance, InHO and PrHo seems to partly exert their effects via increase in serum TNF- alpha levels, NF- kappa B activity and upregulation of glutamate transporters

Low voltage electrical stimulation and wound healing in rabbits: effect of altering frequency

The effect of electrical currents by different modalities on wound healing has been experimented. In this study a survey of the literature shows different results, and the mechanisms of action have not been elucidated for certain. The aim of this study was to compare the results obtained from low voltage-square wave stimulation of different frequencies. Results show that the healing period for the control group [14.9 +/- 0.58 days] was reduced to 11.28 +/- 0.52 and 10.37 +/- 0.7 days for groups receiving 20 and 80 Hz stimulation respectively. This implies that wound closure as an index of wound healing was significantly increased in animals receiving 80 Hz stimulation. Tensile strength was increased from 2013 +/- 192 grams in controls to 2589 +/- 235.1 grams in the 80 Hz-receiving study group. We concluded that electrical stimulation can affect the process of healing and a stimulation of 80Hz is more effective than other frequencies