Ch. 6— Alternatives to Animal Use in Research • 117 
search (93). Further, there has been recent inter- 
est in a specialized feature of some piscine species: 
the electric organ. This tissue is exceptionally rich 
in a single class of cholinergic synapses. Biochem- 
ists, geneticists, and molecular biologists working 
with this material have determined that the struc- 
ture of the acetylcholine receptor protein is re- 
markably like a human’s (39). 
Reduction of Pain or 
Experimental Insult 
Until recently, the probability of a research ani- 
mal receiving the correct amount or type of anes- 
thetic depended largely on the inclination of indi- 
vidual investigators. They could accept information 
about anesthesia available from previous research 
or attempt to improve on it. In some cases where 
little information was available, guesswork was 
required. Now, the enhanced presence of facility 
veterinarians and animal care and use committees 
with oversight authority (see ch. 15) has resulted 
in experimental animals being recognized as veteri- 
nary patients entitled to protection from as much 
pain and distress as possible, while maintaining 
the integrity of research. 
Analgesics, anesthetics, and tranquilizers are the 
principle tools for the reduction of experimental 
pain and distress (see ch. 5). Terminal anesthesia 
and death has become the method of choice follow- 
ing major organ surgery on animals, even though 
it might be argued that observation of the healing 
process logically constitutes a part of surgical re- 
search (224). Where postsurgical study is consid- 
ered necessary, as in cardiology, intensive post- 
operative control of pain can be used in lieu of 
maintaining the animal under general anesthesia 
until death (24). 
Advances in Instrumentation 
New types of instruments are critical to a reduc- 
tion in experimental insult, as they can lead directly 
to the more refined or reduced use of live animals 
or living material. In the past decade, practically 
every piece of instrumentation in biomedical lab- 
oratories has been adapted to handle “micro” sam- 
ples or has been replaced by new microtechnol- 
ogy. Some examples of microinstrumentation 
include: 
• In reproductive physiology, a 1.0 microliter 
sample of rat epididymal fluid collected by 
micropuncture can be used to examine sperm 
motility, determine total protein, and deter- 
mine androgen -binding protein activity (207). 
• In biochemistry and molecular genetics, elec- 
trophysiological techniques are being used to 
explore the possibility of recording the open- 
ing and closing of single membrane channels, 
tiny pores controlling cellular function (105). 
• To study leukemias, blood diseases, and in- 
born errors in metabolism, a method for meas- 
uring the enzyme kinetics within a single white 
blood cell has been developed (134). 
• A device is available that will dispense a 1.0 
microliter sample as 1,000 aliquots (1 nanoliter 
each) for use in biochemical enzyme research 
or for clinical samples such as cerebrospinal 
fluid from infants (97). 
The use of small samples for analysis by mass 
spectrometry (146) and by gas or liquid chroma- 
tography (86,208) exemplifies minimally invasive 
technology. Each year, an entire issue of Science 
magazine is devoted to trends in analytical instru- 
mentation (2,3). Continued developments in ana- 
lytical instrumentation, including noninvasive 
imaging techniques such as magnetic resonance 
imaging (MRI), will likely reduce the experimental 
insults faces by research animals. 
In vivo measurements using fiber optics now pro- 
vide miniaturized spectrophotometric analysis 
from within the ducts and blood vessels, deter- 
mine blood velocity, measure temperature changes, 
monitor intracranial and intracardiac pressure, 
measure fluorescent marker molecules in tumors, 
measure pH, and even determine glucose concen- 
tration (166). Fiber optics offer great promise: They 
can be inserted into vessels and ducts via small 
catheters with little discomfort and into the ab- 
dominal cavity using local anesthetics (a laparos- 
copy), and they can be used repeatedly within the 
same animal to obtain measurements without per- 
manent damage. Chronic intravascular catheters 
are used in a similar way to obtain repeated blood 
samples for hormone measurement from freely 
moving, undisturbed animals (see fig. 6-1) (189). 
Other minimally invasive techniques in animal 
research include immunoscintigraphv, amniocen- 
tesis, and use of the laser. In immunoscintigraphv, 
