Changes of intracellular sodium and potassium ion concentrations in frog spinal motoneurons induced by repetitive synaptic stimulation

A post-tetanic membrane hyperpolarization following repetitive neuronal activity is a commonly observed phenomenon in the isolated frog spinal cord as well as in neurons of other nervous tissues. We have now used double-barrelled Na+- and K+-ion-sensitive microelectrodes to measure the intracellular Na+- and K+-concentrations and also the extracellular K+-concentration of lumbar spinal motoneurons during and after repetitive stimulation of a dorsal root. The results show that the posttetanic membrane hyperpolarization occurred at a time when the intracellular [Na+] reached its maximal value, intracellular [K+] had its lowest level and extracellular [K+] was still elevated. The hyperpolarization was blocked by ouabain and reduced by Li+. These data support the previous suggestion that an electrogenic Na+/K+ pump mode may be the mechanism underlying the post-tetanic membrane hyperpolarization

Evaluating Complementary Therapies for Canine Osteoarthritis—Part II: A Homeopathic Combination Preparation (Zeel®)

A homeopathic combination preparation (HCP) for canine osteoarthritic pain was evaluated in a randomized, double-controlled and double-blinded clinical trial. Forty-four dogs with osteoarthritis (OA) that were randomly allocated into one of three groups completed the study. All dogs were fed test products or placebo for 8 weeks. The dogs were evaluated at the clinic four times, with 4-week intervals. Six different variables were assessed: veterinary-assessed mobility, two force plate variables, an owner-evaluated chronic pain index and pain and locomotion visual analogue scales (VASs). Intake of extra non-steroidal anti-inflammatory drugs was also evaluated. A Chi-squared test and a Mann–Whitney test were used to determine significant improvement between groups. When changed into dichotomous responses of ‘improved’ or ‘not improved’ three out of the six variables showed a significant difference (P = 0.016, P = 0.008, P = 0.039) in improved dogs per group, between the HCP group and the placebo group. The odds ratios were over one for the same variables. As extent of improvement in the variables from start to end of treatment, the HCP product was significantly more improved in four (P = 0.015, P = 0.028, P = 0.049, P = 0.020) of the six variables, compared with the placebo. Our results indicated that the HCP Zeel® was beneficial in alleviating chronic orthopedic pain in dogs although it was not as effective as carprofen