Role of Meconium in the Reaction of Airways Smooth Musculature in the Newborn with Meconium Aspiration Syndrome (Mas).

Abstract

Th e role of meconium in the respiratory system was studied in newborns, who died from various causes ( up to  g of weight). We monitored tracheal rings response to dopamine, serotonin and ethanol in diff erent concentrations (dopamine: , mg/ml, , mg/ml,  mg/ml; serotonin (-HT):  - ,  - ,  - ,  - mol/dm  ; ethanol: , ml, , ml, , ml; ). Tracheal smooth musculature tonus (TSM) was examined in  tracheal preparations taken after the newborn exitus due to diff erent reasons. Based on functional researche of isolated preparations of tracheas, it may be concluded that: aspiration of meconium has not changed the response of TSM to dopamine, serotonin and ethanol (p>,) in comparison with the control group, which have died due to diff erent lung infl ammatory processes (e.g. pneumonia, bronchopneumonia, atelectasis, cerebral hemorrhage). Th e results suggest that meconium does not potentiate the constricting action of dopamine, serotonin and ethanol in tracheobronchial system. Meconium causes mild relaxation of the TSM through a mechanism that is not intermediated by the products of cyclooxygenases (prostaglandins, prostacyclins) from the tracheal epithelium or proteins. Also, as it seems, the direct activity of many tested acids in the smooth musculature has no signifi cant impact on increase of the airways tonus in MAS syndrome. ROLE OF MECONIUM