Gülderen ŞAHİN, Uğur AKSU, Tülin ORUÇ, İbrahim GÜNER, Zeynep YILDIRIM, Karaturan Nermin YELMEN

Anesteziye tavşanlarda santral serotoninin solunum düzenlemesindeki rolü

Çalışmamızda, santral eksojen serotonin'in (5-HT) normoksi ve hipokside solunum düzenlenmesi üzerindeki etkisini belirlemeyi amaçladık. Deneyler urethane (400 mg/kg I.V) ve alpha-chloralose (40 mg/kg I.V) karışımı ile anesteziye edilmiş tavşanlarda yapıldı. İntraserebroventriküler (ICV) 5-HT, sol lateral ventrikül içine stereotaksik yöntemle yerleştirilen kanül aracılığı ile verildi. Soluk frekansı (f/dk), soluk hacmi (VT), solunum dakika hacmi (VE) ve sistemik arteriyel kan basıncı (SAB) kaydedildi ve ortalama sistemik arteriyel basınç (SAOB) hesaplandı. ICV serotonin (20 ug/kg) f/dk ,VT ve VE de anlamlı artışlara neden oldu. Hava fazını takiben, tekrar ICV 5-HT injeksiyonu yapılıp, hipoksik gaz karışımı (% 8 O2-% 92 N2) solutulduğunda, hipokside gözlenen solunum faaliyetindeki artışın daha fazla olduğu saptandı. Tavşanlara ICV ketanserin (5-HT2A/2C reseptör antagonist!', 10 ug/kg) verilmesi f/dk, Vj ve Ve'de anlamlı azalmalara neden olurken, 5-HT'nin ventilasyonda oluşturduğu artışı önledi. Bulgularımız santral ekzojen 5-HT'nin normoksik ve hipoksik ventilasyonu 5-HT2 reseptörleri aracılığı ile artırdığını göstermektedir.

The role of central serotonin on respiratory regulation in anaesthetized rabbits.

In the present study, we aimed to investigate the effect of central exogenous serotonin (5-HT) on ventilation during normoxia and hypoxia. The experiments were performed in peripheral chemoreceptors intact rabbits anesthetized with urethane (400 mg/kg I.V) and alpha-chloralose (40 mg/kg I.V). For intracerebroventricular (ICV) administration of serotonin (5-HT), a cannula was placed intracerebroventricularly to the left lateral ventricle with stereotaxy. Respiratory frequency (f/min), tidal volume (Vf), ventilation minute volume (VE) and systemic arterial blood pressure (BP) were recorded and mean arterial pressure was calculated (Mİİ^B): ICV administration of 5-HT (20 ug/kg) caused an increased in f/dk ,VT and VE. After ICV administration of 5-HT, breathing of hypoxic gas mixture (8 % O2 - 92 % N2) produced an increase in hypoxic respiratory responses. ICV ketanserin administration (5-HT2A/2c receptor antagonist, 10 (g/kg), in rabbits caused a decrease in f/min, VT, and VE. ICV ketanserin also prevented the stimulatory effect of 5-HT on ventilation during normoxia. In conclussion, the results of this study show that 5-HT increases ventilation during normoxia and hypoxia via 5-HT2 receptors.

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