Anti-writhing activity of some peptides related to neurotensin and tuftsin. 
Several small peptides related to neurotensin (NT) and tuftsin were synthesized and tested for analgesic activity against acetic acid induced writhing in mice.  None of the peptides approached the activity shown by NT or NT hexapeptide.  Tuftsin itself was found to be weakly active.  An isosteric dipeptide related to a cobra venom peptide was found to have considerable anti-writhing activity at a high intracerebroventricular dose.