Researchers at two drug companies have devised a non-peptideinhibitor of substance P, a neurotransmitter implicated insending pain messages to the brain, that they suggest could leadto a new class of pain blockers and other drugs.

In addition to its possible role in pain, substance P, a shortpeptide of 11 amino acids, may help regulate the immunesystem and can cause other biological effects, such asinflammation.

Its three receptor types have been cloned, but the peptidesdesigned so far to block the receptors are only weakly activeand, as peptides, they break apart rapidly within the body.

Scientists at Rhone-Poulenc Rorer of France reported last weekin the Proceedings of the National Academy of Sciences thatthey have synthesized and tested a non-peptide blocker ofsubstance P that acts specifically at one of the three receptors.

Judging from animal assays of pain and inflammation, thiscompound will lead, the researchers said, "to a class of drugsthat may be useful in the management of various clinicalpathologies where pain and neurogenic inflammation areinvolved."

Pfizer Inc. researchers, meanwhile, reported in anaccompanying article on their non-peptide antagonist ofsubstance P, which was effective in a rat assay that alsomeasures action at the NK1 receptor, the same site blocked bythe Rhone-Poulenc compound.

The Groton, Conn. company did not report efficacy of itscompound in pain perception or inflammation.

-- Roberta Friedman, Ph.D. Special to BioWorld

(c) 1997 American Health Consultants. All rights reserved.