The effect of the essential oil of Eugenia caryophyllata in animal models of depression and locomotor activity.

OBJECTIVE: The essential oil of Eugenia caryophyllata (clove oil; Family: Myrtaceae) is used in dental care as an antiseptic and analgesic. The present study investigates the effect of clove oil on animal models of depression and locomotion. METHODS: Clove oil was administered in doses of 0.025, 0.05, and 0.1 ml/kg/day, intraperitoneally (i.p.) for 3 weeks. The forced swim test (FST) and the tail suspension test (TST) were used to assess depression. To evaluate locomotor activity, the rota rod test and the photoactometer procedure were performed. RESULTS: In the FST, it was observed that the duration of immobility was significantly decreased (P < 0.01) in animals treated with clove oil (0.05 and 0.1 ml/kg); however, the clove oil dose of 0.025 ml/kg showed an insignificant increase in the immobile period. The TST demonstrated that pretreatment with clove oil decreases (P < 0.01) the immobile period significantly at all the three administered doses. Similarly, the photoactometer procedure showed increased locomotor activity at all the three doses, although significant (P < 0.05) only at 0.1 ml/kg. In addition, the rota rod test showed that animals treated with clove oil (0.1 ml/kg) enhanced muscle coordination as demonstrated by a significant increase (P < 0.05) in the latency to fall from the rota rod as compared to the control. However, the lowest administered dose (0.025 ml/kg, i.p.) decreased the latency to fall from the rota rod significantly (P < 0.05) compared to the control. Clove oil (0.05 ml/kg) also showed a decrease in the latency to fall from the rota rod although the result was not statistically significant. DISCUSSION: Thus, it can be concluded that pretreatment with clove oil decreases depression and enhances locomotor activity similar to that exhibited by psychostimulants.

Role of NMDA and opioid receptors in neuropathic pain induced by chronic constriction injury of sciatic nerve in rats.

BACKGROUND: The efficacy of opioids in neuropathic pain is still controversial. Earlier studies have suggested that N-methyl-D-aspartate (NMDA) receptor binding can be affected by opioids and vice versa. The present study aims to explore the interactions between NMDA and opioid receptors using various combinations of drugs acting on these receptors. METHODS: We used an animal model of sciatic nerve ligation to induce neuropathic pain, and a hot-plate test was used to assess pain response. RESULTS: It was observed that NMDA and naloxone increased the pain response. Ketamine reduced the pain response, which was further reduced when ketamine was administered in combination with naloxone, but not with NMDA, thus highlighting the activity of the NMDA receptor system. In addition, morphine was also found to increase latency to hind-paw lick, which was further reduced when given in combination with naloxone. Furthermore, triple drug combinations using ketamine+morphine+naloxone and ketamine+NMDA+naloxone demonstrated some significant interactions at these receptors. CONCLUSIONS: Thus, our study establishes that neuropathic pain can probably be overcome using higher doses of opioids, and there exists some intimate relationships between NMDA and opioid systems that lead to pain modulation.

Peripheral interaction of opioid and NMDA receptors in inflammatory pain in rats.

Both opioid and NMDA receptors have been known to be involved in pain processing in the central nervous system as well as in the periphery. The effect of drugs acting on opioid and NMDA receptors, and their role in modulation of pain response was observed in the formalin model of inflammatory pain in rats. We have demonstrated that morphine has significant antinociceptive effect in the formalin model and this effect was enhanced when given in combination with ketamine. We have also reported modulation of pain response when naloxone or NMDA were co-administered with morphine or ketamine in various combinations. A noteworthy observation in our study is that low dose naloxone when co-administered with ketamine and morphine, or with ketamine and NMDA, caused decrease in the pain response. These observations may suggest that low dose naloxone can cause modulation of opioid and NMDA receptors resulting in antinociceptive effect. Our study thus introduces a new concept of more than two drugs acting on opioid and NMDA receptors to modulate pain response.

Relationship between iron deficiency anaemia and serum lipid levels in Indian adults.

Both iron deficiency anaemia and dyslipidaemia are widely prevalent public health problems, especially in the Indian population. Some link has been suggested between the two potentially morbid conditions but a sufficient Indian study could not be found in this regard. This study was planned to find the changes in serum lipid profile in adult Indian patients with iron deficiency anaemia and the effect of oral iron therapy on them. Seventy patients with iron deficiency anaemia and 70 age and sex matched healthy controls, in the age group of 18-35 years were investigated for any possible changes in serum lipid profile ie, triglycerides, total cholesterol, high density lipoprotein cholesterol, very low density lipoprotein cholesterol and low density lipoprotein cholesterol. The patients were followed up after 3 months of oral iron therapy. The results are shown as mean +/- standard deviation. Triglycerides and very low density lipoprotein cholesterol levels were found to be significantly (p < 0.001) elevated in the iron deficiency anaemia group (151.87 +/- 48.06 mg/dl and 30.40 +/- 9.71 mg/dl) as compared to controls (109.99 +/- 30.81 mg/dl and 21.96 +/- 6.69 mg/dl), whereas levels of low density lipoprotein cholesterol were found to be significantly (p = 0.02) lower in patients (90.96 +/- 41.55 mg/dl) as compared to controls (105.24 +/- 26.45 mg/dl). However, after treatment (in 43 patients) there was significant (p < 0.001) reduction in the levels of triglycerides and very low density lipoprotein cholesterol (111.56 +/- 26.87 mg/dl and 22.30 +/- 5.36 mg/dl) when compared to their pretreatment levels (154.70 +/- 53.89 mg/dl and 30.93 +/- 10.84 mg/dl), whereas low density lipoprotein cholesterol levels did not show any significant change. These findings indicate that iron deficiency anaemia in Indian adults is attended by abnormal serum lipid profile, which responds significantly to iron therapy.

Effect of hemodialysis on cognitive function in ESRD patients.

BACKGROUND: Uremia is associated with impairment of different cognitive functions. However the pathogenesis of this cognitive dysfunction is unknown. OBJECTIVE: In this study, long-latency event related potentials (ERPs) were used to assess changes in cortical function due to hemodialysis treatment. METHODS: In this cross-sectional study, we measured event related potentials in 15 end stage renal disease (ESRD) patients maintained on hemodialysis, two hours before and two hours after they underwent hemodialysis and compared their data with a strictly age and sex matched healthy control group. The P3 was elicited by using standard auditory "odd-ball" paradigm and the data obtained was statistically analyzed (Wilcoxon signed ranks, Mann Whitney). RESULTS: Before hemodialysis, the patients' P3 latency (347.73 +/- 39.47 ms) was significantly increased as compared with that of healthy control group (308.4 +/- 13.73 ms) (p = 0.001). After hemodialysis, P3 latency of the patients showed a significant decrease (347.73 +/- 39.47 ms to 325.20 +/- 37.15 ms, p = 0.001). P3 latency after dialysis was not significantly different from controls. No significant correlation was noted between various biochemical parameters (hemoglobin, blood urea, creatinine, uric acid and calcium) and P3 latency or amplitude. CONCLUSIONS: Removal of uremic toxins by hemodialysis leads to an improvement in cognitive processing.

Cognitive impairment in chronic kidney disease.

BACKGROUND: Although end-stage renal disease (ESRD) has been associated with cognitive impairment, the relation between lesser degrees of chronic kidney disease (CKD) and cognitive impairment is less well understood. The objective of this study was to assess the cognitive function in patients with varying severity of CKD using P3 event-related potentials (P3ERPs). METHODS: In this cross-sectional study, 15 neurologically asymptomatic (Mini Mental State Examination >24) patients each of CKD stage 3, 4 and 5 (undialysed) were enrolled. Besides this, 15 healthy controls were also studied. All groups were age and sex matched. Glomerular filtration rate (GFR) was estimated using the Modification of Diet in Renal Disease equation. The P300 was studied in all subjects by using standard auditory 'odd-ball' paradigm and the data obtained were statistically analysed. RESULTS: We noted significant prolongation of P300 latencies as severity of CKD increased from stage 3 (318.8 +/- 28.98 ms) to stage 4 (357 +/- 24.65 ms) (P < 0.002) and from stage 4 to 5 (388.47 +/- 31.67 ms) (P < 0.01). P300 latency in CKD stage 3 was not found to be significantly different from controls (308.4 +/- 13.73 ms). Significant positive correlation was noted between serum creatinine, blood urea and uric acid with P3 latency. Significant negative correlation was noted between GFR, serum calcium and haemoglobin with P3 latency. CONCLUSIONS: Increasing severity of CKD is associated with progressive cognitive decline and this may have important clinical consequences.