Fig 1.
Schematic diagram showing the experimental setup. O2·CO2 analyzer to measure the concentration of each gas (%) from the outflow; Differential pressure transducer to measure pressure changes in the chamber; A line, arterial catheter inserted into tail artery; V line, venous catheter inserted into tail vein; Ta and Tb, temperature probes to measure temperature inside the chamber (Ta) and the animal (Tb).
Fig 2.
(a) Protocol 1: Three groups of animals were prepared: NS, DEXMD-5, and DEXMD-50 (n = 7 in each group). All groups received only normal saline for control recording. At the experimental recording, animals received normal saline (NS) or dexmedetomidine (5 or 50 μg·kg−1) (DEXMD-5 and -50). Recordings were performed at 15 and 20 min after intravenous administration of normal saline or dexmedetomidine. (b) Protocol 2: Four groups of animals were prepared: DEXMD-50+ATI-0.5, DEXMD50+EFA-0.5, DEXMD-50+ATI-1.0, and DEXMD-50+EFA-1.0. They were respectively administered dexmedetomidine (50 μg·kg−1) followed 5 min later by 0.5 mg·kg−1 atipamezole (n = 8), 0.5 mg·kg−1 efaroxan (n = 8), 1.0 mg·kg−1 atipamezole (n = 6), or 1.0 mg·kg−1 efaroxan (n = 6), respectively. Recordings were performed at 15 and 20 min after intravenous administration of dexmedetomidine.
Table 1.
Absolute values at control recording (Protocol 1).
Fig 3.
Protocol 1: (a) Respiratory pattern in NS, DEXMD-5, and DEXMD-50, in which the rats were, respectively, given normal saline, dexmedetomidine (5 μg·kg−1), and dexmedetomidine (50 μg·kg−1), at experimental recording (n = 7 in each group). Protocol 2: (b−e) Respiratory patterns in DEXMD-50+ATI-0.5 (n = 8), DEXMD-50+EFA-0.5 (n = 8), DEXMD-50+ATI-1.0 (n = 6), or DEXMD-50+EFA-1.0 (n = 6), in which the rats were, respectively given dexmedetomidine (50 μg·kg−1), followed 5 min later by (b) atipamezole (0.5 mg·kg−1), or (c) efaroxan (0.5 mg·kg−1), or (d) atipamezole (1.0 mg·kg−1), or (e) efaroxan (1.0 mg·kg−1). In Protocol 2, data for the NS are the summed data (n = 21) obtained at control recording in Protocol 1.
Table 2.
Effect of dexmedetomidine (5 μg∙kg−1 or 50 μg∙kg−1) at experimental recording (Protocol 1).
Table 3.
Effect of atipamezole or efaroxan (0.5 mg·kg−1) (Protocol 2).
Table 4.
Effect of atipamezole or efaroxan (1 mg·kg−1) (Protocol 2).