Role of the afferent vagal pathway in modelling of cardio-respiratory response to arvanil in anaesthetized rats
Arvanil is metabolically stable hybrid between anandamide and capsaicin and an agonist of cannabinoid CB1 and vanilloid VR1 receptors. Arvanil is able to alleviate hyperkinesia typical in rat model of Huntington’s disease, spasticity, pain, tremor and other signs of disease in rat model of multiple sclerosis. The drug reveals anti-tumour and anti-infl ammatory action. The present study was designed to test the role of the vagal pathway in post-arvanil cardiorespiratory response. Cardio-respiratory effects of an intravenous injection of arvanil were investigated in 21 urethane-chloralose anaesthetised and spontaneously breathing rats. Bolus injection of 0.8 mg kg-1 of arvanil into the right femoral vein induced in all neurally intact rats a signifi cant increase of tidal volume (VT) and diaphragm activity as well as hypertension coupled with fall in respiratory rate (f). Bilateral midcervical vagotomy precluded the alteration of respiratory parameters without any changes in cardiovascular effects. Arvanil-induced increase in mean arterial blood pressure (MAP) still persisted even after supranodose vagotomy. Results indicated that the respiratory effects evoked by arvanil administered via the peripheral circulation require intact midcervical vagi. Supranodose vagotomy failed to eliminate the hypertension evoked by arvanil.