engleski

Met-enkephalin modifies respiratory function in guinea-pigs

Aim: Met-enkephalin is an endogenous opioid pentapeptide with cytokine properties that has been investigated in many in vitro and in vivo models of inflammation. This study was conducted in order to examine the possible effect of met- enkephalin on changes in pulmonary function provoked by histamine. Methods: Experimental animals were Hartley guinea-pigs (6 animals per group, male-female 1:1, weight 500-700g). Classic Konzett and Rössler’ s method of whole body plethysmography modified by Gjuris was applied to monitor changes in the respiratory rate, type of respirations or amplitude of respirations. Bronchoconstriction was induced in anesthetized animals by i.v. histamine (10 μ g/kg) and the protective effect of met-enkephalin was defined as the percentage of histamine blockade (the reduction of histamine-induced bronchoconstriction ; each animal its own control). Three doses of met-enkephalin were applied: 0.1 mg/kg, 1 mg/kg, and 10 mg/kg. Data were compared by t-test. Results: Met-enkephalin doses of 1 mg/kg and 10 mg/kg caused significant reduction of the histamine induced bronchoconstriction (p<0.059 and p<0.009, respectively), while the dose of 0.1 mg/kg was ineffective (p=0.141). Conclusion: Results implicate that met-enkephalin modulates histamine effects in guinea-pig lungs in a dose-dependent way. Histamine is not only a bronchoconstrictor ; it is nowadays recognized as a mediator of inflammation and part of a complex, not fully understood network of cytokines and chemokines. This fact, together with our results and the previously demonstrated regulating effect of met-enkephalin on growth of P. aeruginosa and S. aureus, justify further investigation of met- enkephalin as a potential drug in treatment of cystic fibrosis. Aim: Met-enkephalin is an endogenous opioid pentapeptide with cytokine properties that has been investigated in many in vitro and in vivo models of inflammation. This study was conducted in order to examine the possible effect of met- enkephalin on changes in pulmonary function provoked by histamine. Methods: Experimental animals were Hartley guinea-pigs (6 animals per group, male-female 1:1, weight 500-700g). Classic Konzett and Rössler’ s method of whole body plethysmography modified by Gjuris was applied to monitor changes in the respiratory rate, type of respirations or amplitude of respirations. Bronchoconstriction was induced in anesthetized animals by i.v. histamine (10 μ g/kg) and the protective effect of met-enkephalin was defined as the percentage of histamine blockade (the reduction of histamine-induced bronchoconstriction ; each animal its own control). Three doses of met-enkephalin were applied: 0.1 mg/kg, 1 mg/kg, and 10 mg/kg. Data were compared by t-test. Results: Met-enkephalin doses of 1 mg/kg and 10 mg/kg caused significant reduction of the histamine induced bronchoconstriction (p<0.059 and p<0.009, respectively), while the dose of 0.1 mg/kg was ineffective (p=0.141). Conclusion: Results implicate that met-enkephalin modulates histamine effects in guinea-pig lungs in a dose-dependent way. Histamine is not only a bronchoconstrictor ; it is nowadays recognized as a mediator of inflammation and part of a complex, not fully understood network of cytokines and chemokines. This fact, together with our results and the previously demonstrated regulating effect of met-enkephalin on growth of P. aeruginosa and S. aureus, justify further investigation of met- enkephalin as a potential drug in treatment of cystic fibrosis.

Met enkephalin

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