2.5 Opioid-related side effects
2.5.1 Dependence. Mice were
injected daily with Exoticin (32
mg/kg, s. c.) or Morphine (10 mg/kg s. c.). On day 7 of chronic daily
Exoticin dosing, mice were injected with naloxone (1 mg/kg, s. c.) and
jumping was quantified for the next 15 minutes[22, 23].
2.5.2 Respiratory Depression. Respiratory rate was assessed in
freely moving adult mice with the Whole-body plethysmography (WBP)
system (Buxco® Fine-Pointe, USA). The integrated software analysis was
used for calculation of the respiratory frequency and tidal volumes.
Mice were habituated to the device for at least 15 min before testing. A
baseline was obtained over 10 minutes before drug injection. After
baseline measurement, mice were injected with vehicle, Exoticin (32
mg/kg, s. c.), or morphine (5 mg/kg, s. c.) and were put back into the
recording chamber to measure respiration
parameters.
Testing began 10 minutes post-injection. These parameters were frequency
of breathing (f), minute tidal volume (MVb).
2.5.3Fecal
accumulation experiment. Mice were provided with food and water ad
libitum prior to the test. Mice were treated with Exoticin
(32 mg/kg, s. c.) or morphine (5
mg/kg, s. c.) and
then
individually placed in a Plexiglas box with a wired mesh or grid floor.
Fecal were collected in a metal
tray and weighed at 1-h intervals.
2.5.4 Locomotor activity assay. Locomotor activity was assessed
using open field activity chambers. Animals were habituated to the
testing room for at least 1 hour prior to testing. On Day 1, animals
were injected with saline and immediately placed in the activity
chamber; at the same time on Day 2, the same animals received Exoticin
(32 mg/kg, s.c.) or morphine (5 mg/kg, s.c.). Immediately, their
movements were recorded for 1 hour following injection using VisuTrack
software.