2.14.1 Drugs
Morphine
sulfate (Hospira, Inc., Lake Forest, IL) and the peripherally acting
mu-opioid agonist DALDA (US Biological Life Sciences, Salem, MA) were
diluted with normal saline and injected subcutaneously at 5
mg∙kg-1.
Isoflurane
(Sigma, St. Louis, MO) mixed in 2.5 l∙min-1 oxygen was
delivered through a nose cone to induce and maintain anesthesia and
ensure the welfare of animals during surgical procedures. All drugs were
weighed and prepared fresh prior to use. Drug doses were determined by
their ED50 and are in line with our previous studies
(Tiwari et al., 2018).