Pharmacological studies of chimeric opioid peptide

Abstract

Opioid peptides are known since ages for their analgesic activity. In the present study, a chimeric opioid peptide was synthesized using Solid Phase Peptide Synthesis. The analgesic effect of the peptide was investigated by tail flick latency assay on male Wistar rats and positive results were observed with the doses of 20, 40 and 60 mg/Kg weight of rat. Pre-treatment with NBI attenuated the analgesia significantly, indicating the involvement of κ- opioid receptors. In tolerance studies, Rats were administered with the chimeric peptide twice daily at a difference of 12 hours and six days data suggested no tolerance development whereas the standard peptide indicated a decrease in analgesia after the day 3 treatment. Further, FACS was carried out using κ opioid receptor expressing transfected CHO cell lines, and the data obtained indicated reappearance of receptors after internalization on binding to the chimeric peptide.