An olive oil-derived antioxidant mixture ameliorates the age-related decline of skeletal muscle function.

Age-related skeletal muscle decline is characterized by the modification of sarcolemma ion channels important to sustain fiber excitability and to prevent metabolic dysfunction. Also, calcium homeostasis and contractile function are impaired. In the aim to understand whether these modifications are related to oxidative damage and can be reverted by antioxidant treatment, we examined the effects of in vivo treatment with an waste water polyphenolic mixture (LACHI MIX HT) supplied by LACHIFARMA S.r.l. Italy containing hydroxytirosol (HT), gallic acid, and homovanillic acid on the skeletal muscles of 27-month-old rats. After 6-week treatment, we found an improvement of chloride ClC-1 channel conductance, pivotal for membrane electrical stability, and of ATP-dependent potassium channel activity, important in coupling excitability with fiber metabolism. Both of them were analyzed using electrophysiological techniques. The treatment also restored the resting cytosolic calcium concentration, the sarcoplasmic reticulum calcium release, and the mechanical threshold for contraction, an index of excitation-contraction coupling mechanism. Muscle weight and blood creatine kinase levels were preserved in LACHI MIX HT-treated aged rats. The antioxidant activity of LACHI MIX HT was confirmed by the reduction of malondialdehyde levels in the brain of the LACHI MIX HT-treated aged rats. In comparison, the administration of purified HT was less effective on all the parameters studied. Although muscle function was not completely recovered, the present study provides evidence of the beneficial effects of LACHI MIX HT, a natural compound, to ameliorate skeletal muscle functional decline due to aging-associated oxidative stress.

Cambios inducidos por el estres en la actividad dopaminérgica de la corteza prefrontal / Stress induced changes in the activates dopaminergic in the prefrontal cortex

Estudiamos los efectos del estrés por inmovilización durante 1,2,3,10 ó 22 días en el metabolismo de la dopamina en la corteza prefrontal de la rata. Determinamos las concentraciones de dopamina (DA), ácido dihidroxifenilacético (DOPAC) y ácido homovanílico (HVA) usando HPLC con detección electroquímica y calculamos las razones DOPAC/DA, HVA/DA y HVA/DOPAC. Encontramos un aumento de las razones DOPAC/DA y HVA/DA al 2§ y 5§ días, que indican un incremento en el metabolismo de DA por el estrés. Además encontramos una segunda fase de activación al día 22 el cual se caracterizó por un incremento significativo de la razón HVA/DA sin cambios en la razón DOPAC/DA. El aumento de la razón HVA/DOPAC los días 2 y 22 sugiere una activación predominante de las vías metabólicas que conducen a la formación de HVA

Aspects of influx and efflux of homovanillic acid of rat cerebrospinal fluid.

In rats, different methods of perfusion (lumbar-cisternal or ventricular-cisternal) with artificial cerebrospinal fluid were performed at velocities of about 30 and 180 microliter/min. Levels of homovanillic acid (HVA) in the outflow were assayed with a semiautomated fluorimetric technique. Intravenous administration of 20 microgram HVA did not substantially enhance the outflow of this acid, indicating that in our preparations HVA found in the perfusate is of central origin. In the lumbar-cisternal preparation probenecid (200 mg/kg, i.p.) was found to inhibit the efflux of a significant fraction of HVA added to the medium, at both perfusion rates. The proportions of HVA eliminated by a probenecid sensitive transport was much higher at the lower rate of perfusion. Following probenecid the increase of endogenous HVA in the ventricular-cisternal perfusate was higher at a lower rate of perfusion. We determined the turnover rate of HVA in the whole brain and compared this value with the HVA outflow in the various preparations. The highest efflux of HVA was found in the ventricular-cisternal preparation during probenecid treatment and did not appear to be dependent upon the rate of perfusion. A maximal value of 3.5% of HVA formed in the central nervous system was found to be released into the cerebrospinal fluid.