An isolation protocol for testing anti-depressants and anxiolytics
in the marmoset monkey
M.J. Jongsma1, S.A.M. van Vliet1,2, R.A.P. Vanwersch1, I.H.C.H.M.
Philippens1,2
1TNO Defence, Security and Safety, Dept. Diagnosis and
Therapy, Rijswijk, The Netherlands
2Utrecht University, Dept. of Psychopharmocology, Utrecht, The Netherlands
Testing of anti-depressants or anxiolytics remains dependent to a great
extent on the use of proper animal models of anxiety and depression.
An ideal model would be one reproducing all features of human anxiety
or depression. Therefore, an isolation protocol in a nonhuman primate
has been developed in which a 'natural' expression of fear and depressive
behavior is present. Separation from the social group is very stressful
for nonhuman primates, elevating anxiety- and depressive-like behaviors.
To test anxiety and depression, different readout-systems were used
resembling depressive-like behavior in human: observational recordings
of anxiety- and depressive-like behavior, human threat test (HTT), startle
reflex, body weight and activity.
" With the observations the occurrence of symptoms correlated to
central effects and the condition of the animal are scored in detail.
The following symptoms are observed: appetite, grooming, apathy (responsiveness
to its surrounding), mobility, stereotypy (repetitive, patterned and
rhythmic movement), stypic behavior (idiosyncratic non-locomotive stereotyped
actions), passive (maintenance of non-locomotive behavior), huddle (fetal-like
self-enclosed position), location (back of cage).
" In the HTT, the response to a human is observed. The following
parameters are recorded: 1) time spent forward on perch, 2) time spent
in nest box, 3) number of forward jumps, 6) body postures: tail postures
(i.e. genital presenting), scent making, arched pilo, 7) Fear postures:
slit stares (flattening of ear tufts and staring through reduced eye
lids), rearing, twisting.
" For the startle reflex and activity computerized test systems
are used.
In the new protocol these tests are performed during normal housing,
during two weeks of isolation, and after re-socialization. During isolation,
all parameters were affected. There was a clear correlation between
the observational and quantitative parameters confirming the anxiety
related behavior. After replacing the animals in the colony, most parameters
recovered to normal. Only the depressive-like behavior was still present.
Paper presented
at Measuring Behavior 2005
, 5th International Conference on Methods and Techniques
in Behavioral Research, 30 August - 2 September 2005, Wageningen, The
Netherlands.
© 2005 Noldus
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