STRUCTURE:
INTRO (why are animals used & ethical concerns, benefits outweigh the costs?)
BODY
STUDY ONE: FREIDMAN:
WHAT IS LEPTIN (Leptin is a hormone that appears to play a role in stopping our eating.
When we eat, our leptin levels rise in line with glucose levels. When leptin reaches a certain level, the
hypothalamus signals that we are “full.” )
WHAT HE DID (He used two mice. One mouse was “normal”, but the other mouse was
hyperphagic. Assumed there was a biological reasoning. He sewed the two mice together, joining their
circulation systems. He found that the hyperphagic mouse lost weight. )
WHAT HE FOUND (This was the beginning of the process that led to the isolation of the
hormone, leptin.)
EVALUATE STUDY ONE:
This research has some serious ethical concerns.
UNDUE STRESS AND HARM: One of the basic ethical standards is to avoid undue stress or harm. It is
clear that this study caused serious physical harm to the mice. They would have to be “humanely” euthanized at the
end of the experiment.
THREE R’s: One of the other guidelines for animal research is the three R’s: Reduce, refine, replace. In
this case, the number of animals was literally two. So, the number was the minimum necessary. However, the
question is whether the procedure could have been refined so that it would not be traumatic for the mice. The
researcher should have had a vet available to oversee the process and to make sure that the mice suffered as
little pain as possible. The final “r”, replace, asks whether the researcher could have used another way to
investigate this question without using the animals. Although it may have taken longer to find certain results,
this might have been done through blood analysis.
STUDY TWO: MEANY:
WHAT WAS HIS AIM (He carried out a study to see if stress in childhood would lead to memory
impairment in old age. )
WHAT HE DID ( Rats from the same litter were allocated to one of two conditions. In one
condition, they were taken away from the mother soon after birth and were groomed by researchers
using brushes. The other condition was taken away from the mother but not groomed. This led to
higher levels of stress – and an increased level of glucocorticoids. → put them in a milky water bath
after 2 years in which they had to find a platform to leave. Easier for groomed mice than the
ungroomed which had higher levels of glucocorticoids since childhood.)
WHAT HE FOUND (Meany argued that high levels of glucocorticoids in childhood led to the
inability to manage stress throughout their life and hippocampal cell death as a result of high cortisol levels,
leading to memory impairment.)
EVALUATE STUDY TWO:
UNDUE STRESS AND HARM (REPLACE?): Meany’s research also has the problem of undue stress
and harm to the animal. He euthanized the rats in order to measure the volume of the hippocampus. At the time of
the research, there was no other way to do this. Today, modern scanning techniques would allow for the rat’s brain
to be measured without having to kill it.
REFINE AND REDUCE: In addition, it was important that Meany used as few rats as possible and that
they are kept in conditions that would be considered as “naturalistic” as possible.
GENERAL EVALUATION:
In both cases, the researcher has to carry out a cost-benefit analysis to justify the research. However,
since the results cannot be known with certainty before doing the experiment, it may be that the expected benefits do
not actually happen.
Friedman: although leptin was discovered, it has not shown to be effective as a treatment for obesity.
However, leptin has been used to explain some cases of obesity.
Meany: the findings support what we see in humans and help researchers to understand the role of cortisol
through experimental methods.
As already mentioned, it is important that the three Rs are used in research.
ONE: REFINE: For example, with refinement – that is, keeping the rats in naturalistic conditions –
researchers can eliminate the stress of confinement. Especially in older research, there is the question of whether the
animals’ stress of being in poor living conditions may have played a role in findings.
Meaney: the level of care for the animal was important so that the stress could be isolated to the lack of
maternal grooming.
TWO: REDUCE: However, the ethical standard of reduction is problematic. If we reduce the numbers
too low, then we cannot be sure that the findings are reliable.
THREE: REPLACE: It is a question whether we can easily replace animals with computer models or in
vitro testing.
Friedman: it would not be possible to create a computer model to find a hormone that we are not sure
exists. Computer models have to be based on a certain amount of knowledge in order to be built.
Meany: Theoretically, he could have used in vitro testing, looking at the effect of glucocorticoids on
hippocampal cells. The problem is that animals, including humans, are systems. Meany’s research showed the
interaction of environment, genetics, hormones, and memory over the lifetime of an animal, something that is not
currently possible with cell cultures. Although in vitro can show us what happens on a micro-level, it does not
allow us to observe behavior that is the result of these changes at the micro-level.