Tissue preparations and solutions
Animals were euthanised by cervical dislocation in accordance with the approved project protocol. Muscle levator auris longus (m. LAL) was quickly removed (Angaut-Petit et al., 1987), then put down onto a Sylgard® chamber with bubbled (95% O2 and 5% CO2) Ringer solution (pH 7.4) containing (in mM): NaCl 135, KCl 5, CaCl2 2, MgCl2 1, NaH2PO4 1, NaHCO3 11.9, glucose 11. Bath solution temperature was controlled by Peltier semiconductor device. Experiments were performed at 20.0 ± 0.3 °C. Muscle contractions were prevented by using µ-conotoxin GIIIB in 2 µM concentration (Hill et al., 1996).