Mlt1l

To confirm the effectiveness of the generation of endotoxemia and detect changes in them as a consequence of GW-788388 treatment, we measured systolic blood pressure (P S ) and instantaneous heart rate (f H ) in conscious animals for up to 72 h after saline or endotoxin treatment with a physiological recording acquisition system and a pressure tail cuff for noninvasive blood pressure recording system for rats (ML125/R), coupled with a MLT125/R pulse transducer (AD Instruments, Castle Hill, Australia). To perform the recordings of P S and f H , animals were conscious and placed in a supine position. Tidal volume (V T ) and instantaneous respiratory frequency (f R ) were measured by transiently introducing (1 min) the rat head into a plastic mask connected to a respiratory flow head (MLT1L, AD Instruments) that measured the ventilatory flow (δV/δt), which was converted into V T through a volumetric differential pressure transducer. All transducers were connected to a PowerLab® 8/30 (AD Instruments), and physiological variables were instantaneously displayed through Chart® software (AD Instruments).

Male adult Sprague Dawley rats were used for these studies. Animals were initially anesthetized with 2% isoflurane. The femoral artery and vein were cannulated to permit monitoring blood pressure and drug administration. The cervical trachea was cannulated and connected to a pneumotachometer (MLT1L, AD Instruments, CO) to measure respiratory flow. The respiratory flow waveform was used to measure respiratory rate (RR) from cycle period, and integrated to calculate tidal volume (VT). Minute volume (V E) was calculated as the product of RR and VT. After these procedures, isoflurane was discontinued and replaced by urethane anesthesia (1.8 g/kg IV). Stable baseline values of cardiorespiratory parameters and arterial blood gases were confirmed before commencing the experimental protocol. Minute ventilation was measured before and after vehicle (saline), GAL-021 (0.3 mg/kg IV) and GAL-160 (0.3 mg/kg IV) injection. GAL-021 and GAL-160 were administered by slow IV bolus to separate groups of animals. Next, the carotid sinus nerves were transected bilaterally at the point where they branch off from the glossopharyngeal nerve and the protocol repeated. Sham-operated animals were included as controls. The ventilatory response to hypoxia (FiO2 = 0.10, 3 min duration) was used to confirm functional denervation of the carotid bodies.