AJP - Regulatory, Integrative and Comparative Physiology, Vol 239, Issue 3 296-R302, Copyright © 1980 by American Physiological Society
Effects of 6-hydroxydopamine and pimozide on temperature maintenance by the chicken
D. L. Rowe-Murphy, A. van Tienhoven, N. R. Scott, P. E. Hillman, C. L. Wood, A. L. Johnson and W. S. Schwark
Intraventricular implants of pimozide in adult white leghorn hens were used
to block dopamine (DA) receptors, and 6-hydroxydopamine (6-OHDA) was
injected intraventricularly to destroy the noradrenergic system locally.
The hens were exposed to ambient temperatures of 5 and 35 degrees C, and
their core temperature was measured. One hundred micrograms of 6-OHDA
significantly reduced the norepinephrine (NE) but not the DA content of the
hypothalamus and reduced the uptake of [3H]NE but not of [3H]DA by
synaptosomes in vitro. Neither of the drug treatments nor their combination
affected average core body temperature (Tb) at either 5 or 35 degrees C.
Pimozide treatment caused a lower maximum Tb at 35 degrees C and a higher
maximum Tb at 5 degrees C than the control treatment. No evidence was
obtained that 6-OHDA treatment affected body temperature regulation. It is
concluded that neither the DA nor the NE system is essential for normal
temperature maintenance in the hen exposed to either 5 or 35 degrees C.
