Renal humoral modulation of skeletal muscle tone in mice: implications for 'the pulmonary-renal cascade'.
The pulmonary-renal cascade may regulate the respiration and skeletal muscle contractility. To evaluate this working hypothetical model, we conducted experiments to ascertain the skeletal muscle tone of the Swiss mice (20-35 g). The animals were evaluated for their skeletal muscle tone via several techniques i.e. inclined plane test, grip strength test and swim test. Groups of mice (n=6) were pre-treated with mefenamic acid (60 mg/kg, i.p), carbenoxolone (100 mg/kg i.p) or vehicle only 15 minutes before the treatment with heparin (500 U/kg, i.v), urokinase (5500 U/kg, i.v) and erythropoietin (150 U/kg, i.v). Heparin potentiated the loss of skeletal muscle tone induced by mefenamic acid and carbenoxolone while urokinase & erythropoietin significantly enhanced the skeletal muscle tone as evaluated by all or one of the tests. Other groups of mice (n=6) were pretreated with mefenamic acid (1 mg i.c.v), carbenoxolone (160 microg i.c.v) or minoxidil (30 microg i.c.v) and the effects of heparin & urokinase and erythropoietin on skeletal muscle tone were evaluated. To study the effects of heparin and urokinase on nerve regeneration, two groups of mice underwent a sham and sciatic nerve crush procedure. The mice treated with urokinase recovered much faster as compared to those treated with heparin or saline. These experimental results suggest that gap junction blockers and potassium channel openers interact with heparin, urokinase and erythropoietin to control the skeletal muscle tone.
Department of Pharmacology, Christian Medical College, Vellore--632 002. tyagi243@yahoo.co.in
Manoj G
MG
Tyagi
S Thirumalai
ST
Velu
Gota S
GS
Vikram
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D000897:Anti-Ulcer Agents / Q000494:pharmacology; D000925:Anticoagulants / Q000494:pharmacology; D002229:Carbenoxolone / Q000494:pharmacology; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006493:Heparin / Q000494:pharmacology; D007276:Injections, Intraventricular; D007668:Kidney / Q000187:drug effects / Q000502:physiology*; D008168:Lung / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008528:Mefenamic Acid / Q000494:pharmacology; D051379:Mice; D008914:Minoxidil / Q000494:pharmacology; D009129:Muscle Tonus / Q000187:drug effects / Q000502:physiology*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology*; D009409:Nerve Crush; D010960:Plasminogen Activators / Q000494:pharmacology; D012584:Sciatic Nerve / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013550:Swimming / Q000502:physiology; D014568:Urokinase-Type Plasminogen Activator / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D000894:Anti-Inflammatory Agents, Non-Steroidal; D000897:Anti-Ulcer Agents; D000925:Anticoagulants; D014665:Vasodilator Agents; D008528:Mefenamic Acid; D008914:Minoxidil; D006493:Heparin; D010960:Plasminogen Activators; D014568:Urokinase-Type Plasminogen Activator; D002229:Carbenoxolone