Endojen Adenozin’in Santral Solunum Kontrol Mekanizmalarına Etkisi

Cal›flmam›zda Na-pentobarbital (25 mg/kg i.v) ile anesteziye edilen intakt (Periferik kimoreseptorleri sa¤lam) ve periferik kimoreseptorleri denerve tavflanlar kullan›ld›. Her iki grup tavflanda sol lateral ventrikul icine adenozin geri-al›m inhibitoru olan dipyridamole (0.05-0.1mg) yan ventrikul icine intraserebroventrikuler (ICV) uygulanarak, endojen adenozinin'in santral solunum kontrol mekanizmalar›na ve hipoksiye karfl› oluflan solunumsal cevaba etkisi incelendi. ‹ntakt ve kimodenerve grup tavflanlara, ICV dipyridamole uygulanmas› oncesinde ve sonras›nda, gerek hava (normoksi) gerek- se hipoksik gaz kar›fl›m› (% 8 O2 - % 92 N2) solutulmas›nda soluk hacmi (VT), solunum frekans› (f/dk.) ve sistemik arteriyel bas›nc (SAB) poligrafta kaydedildi. VT ve f/dk. de¤erlerinden solunum dakika hacmi (VE) hesapland›. . ‹ntakt grup tavflanlara hipoksik gaz kar›fl›m› solutulmas› f/dk., VT, VE ve SAB'da anlaml› art›fllar oluflturdu (p < 0.01, p < 0.05, p < 0.05, p < 0.001). ICV dipyridamole verilmesi ise, VT ve VE'de anlaml› art›fllar meydana getirirken (p < 0.05, p < 0.05), f/dk.'da anlams›z bir azalma oluflturdu. SAB'da ise anlaml› bir azalma gozlendi (p < 0.05). Periferik kimodenerve tavflanlara hipoksik gaz kar›fl›m› solutulmas›nda f/dk., VT, VE ve SAB'da anlaml› azalmalar gozlendi (p < 0.01, p < 0.001, p < 0.001, p < 0.001). ICV dipyridamole ise VT, VE ve SAB'› anlaml› olarak azalt›rken (p < 0.01, p < 0.05, p < 0.001), f/dk.'da anlams›z bir art›fl oluflturdu. Dipyridamole ile birlikte hipoksi uygulanmas›nda benzer bulgular elde edildi. . Sonuc olarak bulgular›m›z, beyinde dipyridamole ile oluflturulan endojen adenozin'in, ventilasyona olan santral etkilerinin, hipoksinin direkt merkezsel etkilerine benzer flekilde, inhibitor nitelikte oldu¤unu gostermektedir. . Anahtar Kelimeler: Hipoksi, ICV dipyridamole, endojen adenozin Cerrahpafla T›p Derg 2006; 37: 92 - 97 Effect of Endogenous Adenosine on Central Respiratory Control Mechanisms. Abstract In this study the effect of endogen adenosine on central respiratory control mechanisms and hypoxic ventilatory responses was investigated. For this purpose dipyridamole, an adenosine reuptake inhibitor was injected into left lateral cerebral ventricle (ICV) of anesthetized (Na-pentobarbital 25 mg/kg i.v) peripheral chemoreceptors intact and chemodenervated rabbits. Systemic arterial blood pressure (BP), tidal volume (VT) and respiratory frequency (f/min) were recorded while the animals were breathing air or hypoxic gas mixture (8 % O2 - 92 % N2) before and after dipyridamole (0.05-0.1mg ICV) administration. f/min, VT ,VE and BP increased significantly during hypoxic gas mixture breathing before dipyridamole administration in intact rabbits (p < 0.01, p < 0.05, p < 0.05, p < 0.001). When dipyridamole was administered (ICV) during air breathing VT and VE increased significantly (p < 0.05, p < 0.05) while no significant decreases was observed in f/min. BP decreased significantly (p < 0.05). On the breathing of hypoxic gas mixture before dipyridamole administration of chemodenervated rabbits, the decreases in f/min,VT ,VE and BP were founded significantly (p < 0.01, p < 0.001, p < 0.001, p < 0.001). ICV administration of dipyridamole during normoxia caused significant decreases in VT, VE and BP (p < 0.01, p < 0.05 p < 0.001) while no significant change was observed in f/min. Comparable findings were obtained when dipyridamole was administered during hypoxic gas mixture breathing. The results of this study show that augmentation of endogenous adenosine in brain with dipyridamole produces a direct inhibitory effect on central respiratory control mechanisms similar to that of hypoxia. KeyWords: Hipoxia, ICV dipyridamole, endogenous adenosine Cerrahpasa J Med 2006; 37: 92 - 97