Introduction to Experimental Pharmacology

1. Experimental
Pharmacology
Dr. Akash Jain
M.M. College of Pharmacy
Mullana, Ambala

2. Pharmacology can be defined as the study of substances that
interact with living systems through chemical process, especially
by binding to regulatory molecules and activating or inhibiting
normal body process
Pharmacology is the science of drugs (Greek: Pharmacon-
drug; logos-discourse). In a broad sense ,it deals with
interaction of exogenously administered chemical molecules
with living systems , or any single chemical substance which
can produce a biological response is a ‘drug’. It importantly
deals with safe and effective use of drugs for medicinal
purposes.
Pharmacology

3. Experimental pharmacology is a biological science, and as such is
related to general biology especially the subjects of anatomy,
physiology, pathology, chemistry and biochemistry.
 The relation to biology is evident, since pharmacology is a study of
the reactions of living material to changes in environment. These
change in environment are usually produced by drugs.
 It is related to anatomy, since this science is necessary as a
foundation of the study of tissues
 If we do not know the anatomy we cannot interpret physiological
reactions .
 it is related to pathology, since the introduction of the drug in itself
is a pathological condition and many drugs readily create distinct
pathological states.
 Drugs are chemicals, and the reactions of the drug with the
organisms is definitely a branch of organic or biologic chemistry.

4.  Father of biology
 Father of pharmacy
 Father of pharmacology
 Father of Indian
Pharmacology
 Father of Modern
Experimental Medicine
 Father of Clinical
Pharmacology
 Father of Medicines
 Father of Chemotherapy
 Aristotle
 Galen
 Oswald Schmiedeberg
 Ram Nath Chopa
 Claude Bernard
 Lou Lasagna
 Hippocrates
 Paul Ehrlich

5. Common name Scientific name
a. Rat
b. Mouse
c. Frog
d. Dog
e. Guinea pig
f. Rabbit
g. monkey
Rattus norvegicus
Mus musculus
Rana tigrina
Canis familaris
Cavia porcellus
Oryctolagus cuniculus
Macaca mulatta

6. Experimental animals
Rodents- Mouse ,Rat , Guinea pig ,
Hamster , Gerbil etc.
Non-rodents –Rabbit ,Monkey , Dog ,
Cat , Pig etc.
Miscellaneous – Fog, Pigeon, Zebra fish,
Chicken,etc.

7. Rodents
Rodents are the mammals which are characterized
by upper and lower pairs of ever–growing rootless
incisor teeth. e.g. Rat , Mouse
Non – rodents
Mammals which are not characterized by ever-
growing incisors in each of upper and lower jaw.

8. NAME OF ANIMAL USE
1) RAT
2) MOUSE
3) FROG
4) GUINEA PIG
 Research of behavior, neuro-science,
immunogenetics, cancer risk
assessment, cardiovascular diseases,
transplantation and ageing
 Research of mutagenesis, cancer,
diabetes, ageing, atherosclerosis,
autoimmune disorders, neurological
dysfunction and other endocrine
disorders.
 CVS and CNS research, cloning
research, embryology, relation
between electricity and the nervous
system.
 For diagnostic tests, enteric
amoebiasis, hypersensitivity,
tuberculosis ,immune response,
anaphylactic shocks, and
encephalomyelitis

9. 5) Rabbit
6) Dog
7) Monkey
 Study of genetics, nutrition,
toxicology, reproduction,
cosmetics, heart disease,
diphtheria, cancer etc.
 Cardiovascular activity, for
diabetes mellitus ,
reproduction, ulcerative colitis,
open heart surgery, organ
transplantation, CNS, safety
pharmacology and toxology.
 Study of drug metabolism,
pharmacokinetic, drugs acting
on CNS, CVS, GIT, and fertility.

10. Contact time –the time i.e., allowed for the drug to remain in contact
with the tissue is called the contact time. The contact time depends
upon the type of the tissue used for example for slow contracting
tissue the contact time allowed is 90secs .
Time cycle – the fixed time cycle is used while recording any effect of
drug on isolated tissue preparation . The fixed time cycle which
comprises of starting of drum recording base line, effect of drug
(contact time) and wash out period . Generally a 5 minutes time cycle
is followed i.e., 30 sec of base line recording, 90 sec of contact time
and subsequent three washing at the interval of each minute.
Magnification value- Distance between fulcrum and writing point(A)
divided by distance between fulcrum and the point of attachment to
the tissue (B).
Recording levers- used to record the contraction or relaxation of the
isolated tissue preparation. They are light in weight, rigid and are
generally made up of wood, aluminium or stainless steel. The is done
on smoked paper fixed on circular cylinder. The levers are of two
types –

11. The common levers used in the laboratories are –
 Simple lever- simplest lever. The celluloid writing tip is attached
at the end of the longer arm. The contraction are recorded as
curved lines.
 Fontal writing lever- it is designed in such a way that the writing
point rotates freely about its axle. The contraction are recorded
as straight lines.
 Starling Heart lever-use to record the contraction of the heart.
The difference between this lever and other isotonic lever is that
the fulcrum lies at one end beyond the point of attachment.
 Brodie’s universal lever – it is general utility lever.
1) Isotonic type – change in length due to contraction is recorded
while the tension on the muscle remain the same e.g., simple
lever, frontal lever
2) Isometric type –measures increase in tension of the tissue when
the length of the tissue is kept constant.

12. Bioassay is defined as comparative assessment of relative potency of a
test compound to a standard compound on any living animal or
biological tissue.
This procedure is for determining the quantitative relationship between
the concentrations (dose) and magnitude of response. Bioassay can be
defined as the procedures to check the nature and potency of drug by
using biological system i.e., using living systems like in-vitro, organ,
tissue or even whole organism . Broadly bioassay is classified into three
groups -
a) Direct end point assay
b) Quantal assay
c) Graded assay- it is further of the following types-
1.Bracketing assay
2.Matching assay
3.Interpolation assay
4.Multiple point assay

13. DIRECT END POINT ASSAY- the threshold dose required for response is
determined for each experimental unit. The principle of direct assay is to
measure direct response of dose of standard and test preparation. The
ratio between these doses estimates the potency of the preparation
relative to the standard.
The threshold dose of standard=total period of infusion*rate of drug
administration
QUANTAL ASSAY (ALL OR NON-ASSAY)- the unknown is compared with
the standard with respect to potency which produces the quantal affect,
i.e. changes is easily recognized sign or often death.
GRADED RESPONSE ASSAY-in this type of bioassay the extent of the
reaction is a function of the dose of the drug.
Bracketing assay- preferred when test sample volume is too small. A few
responses are taken by using any test drug concentration. Consequently,
this response is bracketed between two responses (one higher and one
lower) of the standard drug. Then potency of the test drug is directly
calculated from concentration of standard drug or by interpolation
through dose response curves.

14. Matching assay- comparison of potency between the unknown and
standard drug is done by trial and error method. In this method
response is matched at only one dose , so it does not needs dose
response curve of test compound.
Interpolation assay-this method depends on the assumption of
dose response curve. concentration of unknown is interpolated from
the dose response curve graph.
Multiple point assay-repeated response recording in graded
response assays minimize the tissue sensitivity errors and improve
the methodological errors. These assays are performed by the
selection of 1 or more dose responses of test compound and these
responses are compared with 2 or more responses of standards. The
selection of the test doses must be in the linear portion of the dose-
response plot of standard compound, I.e. between 25-75%. It is
further of three types-
1.three-point assay
2.four-point assay
3.six-point and eight-point assay

15. 1. Student organ bath
2. Levers
3. Mechanical
kymograph
4. Smoked drum
 Rudolph Magnus
 Archimedes
 Carl Ludwig
 Charles Scott
Sherrington and
Henry Starling

16. Name of instrument Use
1. Elevated Plus Maze
2. Morris Water Maze
3. Analgesiometer (tail flick,
hotplate)
4. Convulsiometer
5. Actophotometer
 For selective identification of
anxiogenic and anxiolytic drugs
effect in rodents and to evaluate the
learning and memory in rodents in
presence or absence of drug.
 To evaluate learning and memory in
rodents and to evaluate effect of
drugs.
 To identify any pain stimulus
threshold in rodents against a radiant
heat and to screen analgesic drugs
by increasing pain threshold.
 Used to induce convulsions
experimentally which are
hypothesized to originate from
forebrain and brainstem.
 To measure locomotor activity
(horizontal activity)

17. 6. Pole Climbing
Apparatus
7. Rotarod apparatus
8.Eddy’s Hot Plate
.
 To study antipsychotic drugs,
cognitive function, mainly
response to conditioned
stimuli during learning and
retention.
 To measure parameters such
as riding time or endurance,
evaluating balance, grip
strength and motor
coordination of the test
subjects.
 Used in basic pain research
and in testing the effectiveness
of analgesics by observing the
reaction to pain caused by
heat.

18.  General Definition
 IN VITRO
In vitro studies are performed with microorganisms, cells, or
biological molecules outside their normal biological context in
controlled environment
 IN VIVO
In vivo studies refers to experimentation using a whole, living
organism as opposed to a partial or dead organism.
 ALBINO – A person or an animal having a congenital absence of
pigment in the skin and hair and eyes (which are pink).in such
organism the albino gene is introduced which leads to lack of melanin
production.
 Albino gene – gene which suppress the melanin in an organism in
which it is inserted and leads to white skin and white hair.
 Knockout – selective gene is taken out.
 Knock in - selective gene of interest is introduced into an organism .

19.  References
 1. Kulkarni S. K. Hand book of experimental
pharmacology. Vallabh Prakashan, Delhi
 2. Bronswijk and Cohen. The first recordings
of pharmacological effects. British Journal of
Clinical Pharmacology. 2008; 66(5):588–593