BASICS OF EXPERIMENTAL PHARMACOLOGY
PHARMACOLOGY is the science which deals with study of drugs
EXPERIMENTAL PHARMACOLOGY: deals with effect of various pharmacological agents
studied on different animal species
AIMS :
• Find out the therapeutic agent suitable for human use
• Study the toxicity of the drugs
• Study the mechanism and site of action of drugs
•
Pharmacology
Discovery of new drugs or to study the actions of existing drugs
Preclinical
Clinical
Two ways
1) Intact animal study – invivo
2) isolated organ study – invitro
Phase -1,2,3,4
Experimental pharmacology – great imp
Experimenter should take outmost care
Sacrificing - humane
Euthanasia – painless killing
Laboratory animals – breaded and handled in laboratory
•Mice
•Rat
•Guinea pig
•Rabbits
RAT
species Rattus norvegicus
Wister starin is commonly used
Other strains –
•Wistar rat
•Sprague Dawley rat
•Biobreeding rat
Wistar rat
•Long-Evans rat
•Zucker rat
•Hairless rats
•RCS rats
•Shaking rat Kawasaki
Sprague Dawley rat
Genetically
modified
rats
Hairless rats
Zucker rat
ADVANTAGES AND CHARACTERISTICS
• small in size
• drug to be tested required in small quantity
• vomiting center is absent – oral administration can be done
• gall bladder and tonsils are absent
Continuous flow of bile into intestine
This facilitates the study of the drugs acting on bile, cholesterol reabsorbing
ect
• pancreas are diffused therefore difficult to produce panereactomy
• stomach, fundus and pyloric parts are clear lining between them
•Gastric acid secretion is continuous
EXPERIMENTAL USE
• psychopharmacological studies
• study of analgesics and anticonvulsants
• bioassay of various hormones, such as insulin, oxytocin, vasopressin
•Study of estrus cycle, mating behavior and lactation
• isolated tissue pre’s
• chronic study
•Gastric acid secretion
• hepatotoxicity studies
• study on mast cells
MICE ( Mus musculus)
ADVANTAGES
• Smallest
•Easy to handle
•Cheap
•Less drug required
EXPERIMENTAL USES
• toxicological studies
• teratogenicity studies
• bioassay of insulin’ screening of analgesic and anticonvulsant
•Screening of chemotherapeutic agents
• studies related to genetics and cancer research
• drugs action on CNS
Swiss albino mice are commonly used species
Other strains are – Balb/C and C-57
GUINEA PIGS ( CAVIA PORCELLUS )
• docile animals
• highly susceptible to TB and anaphylaxis
•Highly sensitive to histamine, penicillin
•Required exogenous vit c in diet
EXPERIMENTAL USES
• evaluation of bronchodilators
• anaphylactic and immunological studies
• study of histamine and antihistamines
• bioassay of digitalis
• evaluation of local anesthetics
• hearing experiments because of sensitive cochlea
• isolated tissues especially ileum, heart
• study on TB and ascorbic acid metabolism
RABBITS (Lupas cuniculus)
• Docile animal
• New Zealand white strains are widely used
• it has huge caceum and long appendix
• enzyme atropine esterase is present in rabbit liver and plasma so it can tolerate large
doses of belladona (atropine)
EXPERIMENTAL USES
• pyrogen testing
• bioassay of anti-diabetic, curareform drugs and sex hormones
• screening of agents affecting capillary permeability
• drugs used in glaucoma
• pharmacokinetic studies
• studies related to antifertility agents
• isolated preparations like heart, duodenum, ileum, pre’s
• study on local anaestetics
•Study on miotic and mydratics
FROGS (RANA TIGRINA)
•Most commonly used in physiology, pharmacology and toxicoloty
• used before 200 years
• amphibian animal safe to handle
•Cannot breed in lab
EXPERIMENTAL USES
• isolated preparations, heart, rectus abdominis muscle
• drugs acting on CNS
•Drugs acting on NMJ