ABSTRACT
In order to characterize the role of sympathetic activity in obesity, we repeatedly assessed sympathetic activity via power spectral analyses of heart rate variability in the same subjects at 7, 11, 25, and 60 weeks, using monosodium glutamate (MSG)-induced obese and control rats. The effects of lower sympathetic activity on obesity were also evaluated. Fat mass in MSG rats was already higher at 7 weeks, but the sympathetic activity did not differ between 7 and 25 weeks. Between 25 and 60 weeks, the increase in fat mass, food efficiency, and body weight gain was higher in MSG rats. The increase in sympathetic activity between 25 and 60 weeks and sympathetic activity at 60 weeks were lower in MSG rats. Fat mass at 60 weeks was inversely correlated with changes in sympathetic activity between 25 and 60 weeks. Reduced plasma epinephrine levels by bilateral adrenal demedullation induced increase of fat mass. In summary, an attenuated increase of sympathetic activity with age may partly be responsible for aggravated obesity in MSG rats. Additionally, reduced sympathetic activity per se induced obesity in rats. These results suggest that lower sympathetic activity contributes to obesity in rats.
Subject(s)
Animals , Rats , Body Weight , Epinephrine , Guanethidine , Heart Rate , Obesity , Plasma , Sodium GlutamateABSTRACT
BACKGROUND: Treatments of neuropathic pain were included Ca blocker, steroid medication, epidural or spinal local anesthetics, intravenous reserpine and phenoxybenzamine and operative sympathectomy. This study was performed to evaluation the effects of laser radiation and intraperitoneal guanethidine to the neuropathic pain. METHODS: The neuropathic pain were produced by the tight ligation of L5 and L6 spinal nerves in the adult rats (Sprague-Dawley) withdrawl response to the non-noxious stimulation(mechanical allodynia) were increased and response to the cold stimulation (cold allodynia) were increased too. After that, we injected 50 mg/kg guanethidine intraperitoneally and radiated the He-Ne laser to the operated site to evaluate the effect of chemical sympathectomy and laser radiation. RESULTS: Mechanical allodynia was significantly reduced(p<0.05) 1st and 2nd day after chemical sympathectomy. Cold allodynia was significantly reduced(p<0.05) 1st day after chemical sympathectomy. Mechanical and cold allodynia were not significantly reduced after laser radiation. CONCLUSIONS: It was suggested that the chemical sympathectomy via intraperitoneal injection of guanethidine 50 mg/kg had the therapeutic effect of neuropathic pain in the surgically operated rat which was ligated L5, 6 spinal nerve.
Subject(s)
Adult , Animals , Humans , Rats , Anesthetics, Local , Guanethidine , Hyperalgesia , Injections, Intraperitoneal , Ligation , Neuralgia , Phenoxybenzamine , Reserpine , Spinal Nerves , Sympathectomy , Sympathectomy, Chemical , Sympathetic Nervous SystemABSTRACT
We produced the cauaalgiform pain by unilateral 1/3-1/2 ligation of sciatic nerve in rats.. Withdrawal thresholds to non-noxious stimulation were reduced(mechanical allodynia), and withdrawal thresholds to heat stimulation were reduced(heat hyperalgesia) too. After that, we injected 50 mg/kg guanethidine intraperitoneally for the study of the effects of chemical sympathectomy in postopertive 7th day, 37th day respectively. The results were as follows 1) Mechanical allodynia was alleviated partially in 12 hours, first day after sympathectomy. 2) Heat hypera1gesia was alleviated completely in first day to 4th day after sympathectomy, and reappeared after 5th day.