Ch. 5— The Use of Animals in Research • 93 
Left: Bent, flexed posture and absence of movement 
exhibited by a rhesus monkey treated with the drug 
MPTP to induce Parkinson’s disease. Other symptoms 
in both monkeys and humans include tremor, eyelid 
closure, difficulty swallowing (drooling), and difficulty 
with vocalization and speech. 
Right: Reversal of abnormal posture and return of nor- 
mal movement following treatment with L-dopa. The 
right photograph was taken 2 hours after the left one. 
Photo credit: R. Stanley Burns, National Institute of Mental Health 
First animal model of Parkinson’s disease, developed in 1983 
a limited number of rhesus monkeys reaching 25 
to 30 years of age (11). In 1984, hot flashes were 
described in another primate, the stumptail mon- 
key (25). The aim of developing an animal model 
for hot flashes is to determine the role of the brain 
and of hormones in the control of this problem. 
Once the underlying mechanisms that produce 
hot flashes are better understood, more effective 
treatments may be developed for women who 
suffer from menopausal problems. 
