Nutrient deficiencies as a risk factor in Taiwanese patients with postherpetic neuralgia.

Postherpetic neuralgia (PHN) is the most common complication of herpes zoster (HZ). The aim of the present study was to compare the nutritional status of PHN patients with that of healthy controls, and then to identify risk factors for PHN using multivariate multiple logistic regressions. In the present cross-sectional study, we prospectively enrolled fifty PHN patients for at least 3 months and fifty healthy controls. We selected nine circulating nutrients including ionised Ca, Zn, retinol, folic acid, vitamin B12, vitamin C, α-tocopherol, γ-tocopherol and lycopene associated with both immunity and the modulation of neuropathic pain, and measured their concentrations in plasma/serum. Concentrations of ionised Ca, Zn, vitamin C and vitamin B12 were significantly lower in PHN patients than in controls after excluding those patients receiving supplements since the outbreak of HZ. The prevalence of either mild/marginal or severe deficiencies for any of the nine selected circulating nutrients in PHN patients (92 %) was much higher than that in controls (46 %) (P < 0·001). Lower concentrations of vitamin C ( ≤ 45·0 µmol/l), ionised Ca ( ≤ 1·05 mmol/l) and Zn ( ≤ 0·91 g/l) were found to increase independently the risk of PHN using binary variable (dichotomy) analyses with both PHN patients and controls in a multivariate logistic regression analysis. No significant correlations existed between the risks of PHN and the concentrations of retinol, folic acid, vitamin B12, lycopene or α:γ-tocopherol ratios. Thus, lower concentrations of circulating nutrients, namely vitamin C, ionised Ca or Zn, are probably a risk factor in Taiwanese patients with PHN.

Plasma glucose lowering mechanisms of catalpol, an active principle from roots of Rehmannia glutinosa, in streptozotocin-induced diabetic rats.

Catalpol is one of the active principles from roots of Rehmannia glutinosa Steud (Scrophulariaceae) that is widely used to treat diabetic disorders in Chinese traditional medicine using the name of Di-Huang, which is used to investigate the mechanisms for lowering of plasma glucose in streptozotocin-induced diabetic rats (STZ-diabetic rats). Catalpol decreased plasma glucose in a dose-related manner, and this action was reduced by pretreatment with naloxone or naloxonazine. An increase of plasma ß-endorphin by catalpol was also observed in parallel. The plasma glucose lowering action of catalpol was deleted in bilateral adrenalectomized rats. Moreover, catalpol enhanced ß-endorphin release from the isolated adrenal medulla of STZ-diabetic rats. Otherwise, plasma glucose lowering action of catalpol failed to produce in opioid µ-receptor knockout mice. Also, repeated administration of catalpol for 3 days in STZ-diabetic rats resulted in a marked reduction of phosphoenolpyruvate carboxykinase (PEPCK) expression in liver and an increased expression of glucose transporter subtype 4 (GLUT 4) in skeletal muscle. These effects were also reversed by blockade of opioid µ-receptors. Our results suggested that catalpol increased glucose utilization through increase of ß-endorphin secretion from adrenal gland in STZ-diabetic rats.

Epinephrine, phenylephrine, and methoxamine induce infiltrative anesthesia via alpha1-adrenoceptors in rats.

AIM: To assess whether epinephrine, phenylephrine, and methoxamine act via certain subtypes of adrenoceptors to exert their local anesthetic activity. METHODS: We investigated cutaneous anesthesia from adrenoceptor agonists and/or antagonists in conscious, unanesthetized Sprague-Dawley male rats (weight 200-250 g). Cutaneous anesthesia was evidenced by a block of the cutaneous trunci muscle reflex, which is characterized by reflex movement of the skin over the back produced by twitches of lateral thoracispinal muscles in response to local dorsal cutaneous noxious pinprick. RESULTS: Local infiltration of epinephrine, L-phenylephrine, or methoxamine alone induces cutaneous anesthesia in rats in a dose-dependent way. Epinephrine is found to be 19 and 29 times more potent than those of methoxamine and L-phenylephrine, respectively. The cutaneous anesthesia induced by epinephrine, phenylephrine, or methoxamine can be significantly reduced by alpha(1)-adrenoceptor antagonists (eg, prazosin), alpha1, alpha2-adrenoceptor antagonist, alpha(1A)-adrenoceptor antagonist (eg, 5-methylurapdil), alpha(1B)-adrenoceptor antagonist (eg, chloroethylclonidine), or alpha(1D)-adrenoceptor antagonist (eg, BMY7873). CONCLUSION: Our results indicate that epinephrine, phenylephrine and methoxamine all act mainly via mixed subtypes of alpha(1)-adrenoceptors to induce cutaneous anesthesia in the rat.

The antinociceptive and anti-inflammatory effects of five depot formulations of ketorolac propyl ester in rats.

BACKGROUND: Ketorolac is a potent nonsteroidal anti-inflammatory drug. Recently, a ketorolac prodrug, ketorolac propyl ester, was synthesized in our laboratory. The aim of the study was to evaluate the antinociceptive and anti-inflammatory effects of ketorolac propyl ester in five depot formulations. The vehicles used in these formulations were injectable vegetable oils, i.e., sesame oil, peanut oil, soybean oil, castor oil, and cottonseed oil. The traditional therapentic form of ketorolac tromethamine in saline was used as control. METHODS: Six studies were carried out to test the antinociceptive and anti-inflammatory effects of intramuscular ketorolac tromethamine (in saline) and its propyl ester (in five depot formulations) 240 micromol/kg on Sprague-Dawley rats treated with intraplantar carrageenin. RESULTS: Ketorolac tromethamine (in saline) produced an 8 h duration of action on both antinociception and anti-inflammation, whereas ketorolac propyl ester in five oily vehicles produced 54- to 78-h durations of actions in both antinociception and anti-inflammation. Ketorolac propyl ester in cottonseed oil produced a duration of action of 78h in both antinociception and anti-inflammation. CONCLUSIONS: All five depot formulations of ketorolac propyl ester produced longer durations of antinociceptive and anti-inflammatory effects.