Chickens can serve as biomedical model for human headaches
Dec. 4, 2007Contact Information:
Dr. Wayne Kuenzel, Professor of Poultry Science; Physiology/neural biology
479-575-6112 / wkuenzel@uark.edu
By Fred Miller, Science Editor
479-575-5647, fmiller@uark.edu
Poultry physiologist Wayne Kuenzel led a research team that showed how chicken brains can be used as a model for studying headaches in humans.Wayne Kuenzel, a physiologist studying the neural biology of poultry brains, led a team of Arkansas scientists that determined a diet low in vitamin A leads to an increase of pressure in cerebrospinal fluid in the brain. In humans this condition, known as intracranial hypertension, is a known cause of severe headaches for which no remedy is available.
Emanuel Tanne, M.D., president of the Intracranial Hypertension Research Foundation of Vancouver, Wash., asked Kuenzel to investigate whether chickens could serve as a model for research on this condition, and the foundation provided a grant for the work.
Kuenzel said research in Great Britain in the 1950s showed that vitamin A-deficient diets raised intracranial pressure in chickens, but no work had been done to confirm the results nor determine how deficient the diet had to be in Vitamin A to obtain significant increases in intercranial cerebrospinal fluid pressure.
Graduate students Padmakumar Pillai and Tanika O'Conner-Dennie prepared diets formulated by their graduate advisor, nutritionist Jason Emmert, that were deficient in vitamin A for the test birds. Using an instrument developed for the research by poultry physiologist Robert Wideman, Kuenzel and honors student Amanda Rowland tracked intracranial pressure in the cerebrospinal fluid of test birds and of control birds fed a normal diet.
Kuenzel said a diet with only 25 percent of the daily requirement of vitamin A led to an increase of more than 60 percent in intracranial pressure. "In humans, with that kind of pressure, you'd probably have a headache," he said.
The build-up of pressure in this manner takes weeks, Kuenzel said. To shorten the time required, he tested a reversible surgical procedure, suggested by Wideman, to obstruct the jugular veins, restricting the flow of blood leaving the head. The restriction also affects the drainage of excess cerebrospinal fluid from the brain.
Kuenzel said the procedure raises intracranial pressure to the same level as a vitamin A-deficient diet in a matter of hours instead of weeks. "This procedure can be used in research to determine the effects of poor circulation in humans," he said.
Once the occlusion is released, intracranial pressure soon returns to normal, Kuenzel said.
The research developed two methods to produce increased intracranial pressure in chickens, including a surgical procedure and instrumentation that accurately measures the pressure. "Future experiments using chickens as a biomedical model could be applied to humans for research aimed at finding remedies for headaches caused by intracranial hypertension," he said.
Results of the research were published in the journal Poultry Science, volume 85, pages 537-545.