Mayo researchers patent compounds that might treat schizophrenia and Parkinson's disease

Wednesday, May 09, 2001

JACKSONVILLE, Fla., May 9, 2001 — The United States Patent Office has issued a patent to Mayo Foundation for Medical Education and Research for a new amino acid that may be useful in the treatment of schizophrenia and Parkinson's disease. The amino acid, called neo-tryptophan, was created by a team of Mayo researchers led by Elliott Richelson, M.D.; Yuan-Ping Pang, Ph.D.; and Daniel McCormick, Ph.D. Other co-inventors on the patent are Mona Boules, Ph.D.; Abdul Fauq, Ph.D.; Beth McMahon, Ph.D.; and Bernadette Cusack. The patent covers the amino acid and any peptide that contains it.

Since the early 1980s scientists have suspected that neurotensin, a peptide comprised of 13 amino acids that is present in the brain, is a natural anti-psychotic. About 15 years ago, Dr. Richelson, a psychiatrist and neuropsychopharmacologist, became intrigued with the idea of developing neurotensin-like compounds as possible novel anti-psychotic drugs. When introduced into the brain, these neurotensin analogs would activate neurotensin receptors. Unlike neurotensin itself, these analogs would not be as susceptible to enzymatic degradation and would therefore have longer-lasting effects.

Richelson and his colleagues began to change systematically the sequence of the 8-13 amino acid portion of the molecule. In the process of developing about 80 different neurotensin 8-13 analogs, they discovered some features of the molecule conferred better activity at a human neurotensin receptor than at a rat receptor. Specifically, they figured out the structure of a substitute for the tyrosine in the 11th position of the molecule that would fit better into the human receptor. They created an amino acid similar to tryptophan that had the right three-dimensional configuration to replace the tyrosine. Dubbed neo-tryptophan, this new amino acid, when it was substituted into the peptide, markedly increased binding of the peptide to the human receptor.

"As a clinician, I know there is a definite need for new drugs to treat schizophrenia or Parkinson's disease," says Dr. Richelson. "So, we are working hard to get where we can test whether one of our compounds has clinical usefulness."

Dr. Richelson is seeking Food and Drug Administration (FDA) approval to begin testing a neo-tryptophan containing peptide as a drug for treating schizophrenia and Parkinson's disease. He says this peptide also has analgesic properties and lowers body temperature, so researchers are interested in testing them to preserve neurons in the brain after an anoxic event such as cardiac arrest. He hopes clinical trials in human control subjects may be underway by the end of the year.

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Media contact: Erik Kaldor 904-953-2299 kaldor.erik@mayo.edu

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