which was resolved by fractional crystallization of the diastereoisomeric CAL-101 CAL-101 870281-82-6 870281-82-6 dibenzoyltartaric acid salts, and this material was used for synthesis of the respective enantiomeric products. The enantiomeric purity of the chiral products was determined using chiral HPLC analysis on CHIRALPAC® AD H analytical column. Rimonabant 1 4 methyl N 1H pyrazole 3 carboxamide and SR144528 1 N 1 H pyrazole 3 carboxamide were provided by the National Institute on Drug Abuse. Naloxone hydrochloride dihydrate, morphine sulfate, and dimethyl sulfoxide were purchased fromSigma Aldrich.All drugs delivered intraperitoneally were dissolved in a vehicle of 100% DMSO.
This is the same vehicle that has been employed in previous work.
Cannabinoids were dissolved in a volume of 1 ml/kg bodyweight buy CAL-101 with the following exceptions. Morphine was dissolved in DMSO and administered subcutaneously in a volume of 1 ml/kg. Thus, the volume of DMSO administered was uniform between animals in all studies involving systemically administered agonists. Naloxone was dissolved in saline and administered locally into the dorsal surface of buy CAL-101 the paw as described previously or intraperitoneally in a volume of 1 ml/kg. Baseline responses to mechanical stimulation to the hindpaw were evaluated at least 1 h prior to evaluation of baseline responses to thermal stimulation. In a subset of experiments, the order of baseline testing was reversed.
This modification enabled us to confirm that hypersensitivity to thermal or mechanical stimulation was not produced by the order of testing mechanical and thermal responses.
Following completion of baseline testing, all rats were returned to their home cages for approximately 2 h prior to administration of drug or vehicle. All studies were conducted by a single experimenter who was blinded to the drug conditions.Animals were randomly assigned to drug or vehicle treatments. Mechanical withdrawal thresholds were assessed using a digital Electrovonfrey Anesthesiometer equipped with a rigid tip. Rats were placed underneath inverted plastic cages and positioned on an elevated mesh platform. Rats were allowed 10 15 min to habituate to the chamber prior to testing.
Stimulation was applied to themidplantar region of the hindpaw through the floor of a mesh platform.
Mechanical stimulation was terminated upon paw withdrawal, consequently, there was no upper threshold limit set for termination of a trial. Mechanical paw withdrawal thresholds are reported as the mean of duplicate determinations averaged across paws. Paw withdrawal latencies to radiant heat were measured in duplicate for each paw using the Hargreaves test and a commercially available plantar stimulation unit. Rats were placed underneath inverted plastic cages positioned on an elevated glass platform. Rats were allowed 10 15 min to habituate to the chamber prior to testing. Radiant heat was presented to the midplantar region of the hindpaw through the floor of the glass platform. The intensity of the heat source was adjusted such that an average baseline latency of approximately 20 s was achieved. Stimulation was terminated upon paw withdrawal or after 40 s to prevent tissue damage. Thermal paw withdrawal latencies are reported as the mean of dupli