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Adrenaline is a hormone and a neurotransmitter. It can be quantified by measuring its potency.
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Department of Pharmacology Sree Siddaganga college of Pharmacy
Tumkur-572 102Karnataka
WHAT IS ADRENALINE?
Adrenaline or epinephrine is a hormone released from the adrenal gland.
It is one of the major neurotransmitters is the body.
HOW DOES ADRENALINE ACT ?
Adrenaline acts through receptor mechanisms, in the sympathetic nervous system.
The receptors being α and β receptors.
What is the use of adrenaline?
It is often used in cardiac resuscitation
To reverse severe allergic reaction.
People who are allergic to bees may carry an Epi-Pen.
How is Adrenaline bioassayed ?
PREPARATIONS ACTIVITY ASSAYED
Blood pressure of spinal cat
Rise in B.P
Isolated rabbit duodenum Isolated caecum of fowl Isolated rat uterus
Inhibition of the tone
Standard Preparation Adrenaline standard
solution is prepared in 0.1 N HCl.
Dilutions are made with saline.
Suitable concentration is 1:10,000
Method using Anaesthetised Dog:
A medium size dog(10-13kg) is anaesthetised with phenobarbitone sodium in a dose of 25 mg/kg i.v.
B.P is recorded on a kymograph after cannulating carotid artery with arterial cannula , connected with mercury manometer.
The animal should be given 0.001-0.002 mg of atopine to paralyse the vagus nerve.
Adrenaline is injected into the femoral vein through venous cannula.
Two successive responses of the same dose of adrenaline are noted.
The similar responses after same
doses, is an indication that there is
no variation in BP.Then the test and standard
samples are given in alternate till
both produce similar rise in BP.
Method Using Rabbit’s Duodenum:
A rabbit weighing 2-3 kg is killed by headblow method.
Dissected and duodenum is isolated.
The duodenum is suspended in the inner bath of mammalian organ bath.
Inner bath is filled with Tyrode solution, maintained at 37.5 0C.
Muscle allowed to stabilize for 30 mins.
Rhythmic contractions are recorded by means of the isotonic frontal writing lever on the kymograph.
Adrenaline relaxes the duodenum.
De Jalon’s Method on Rat’s Uterus:
A virgin female rat (100-150 g) is used.
The rat is killed by headblow method.
Abdomen opened, uterine horns are isolated and placed in De Jalon solution
De Jalon's solution
NaCl - 9.0gmKCl - 0.42gm CaCl2 - 0.06gm NaHCO3 - 0.5gm Glucose - 0.5 gm/L
Uterine horns are ligated and suspended in mammalian organ bath containing modified ringer solution.NaCl - 9.0 gmCaCl2 - 0.06 gmKCl - 0.45 gmDextrose – 0.5 gmNaHCO3 – 0.5 gmDistilled water – 1000 ml
Two identical contractions for 30 seconds with carbochol are recorded (0.75 mcg/ml)
Response from 3 different doses of standard adrenaline and 1 intermediate dose test adrenaline is recorded.
The percentage reduction in carbochol induced contractions are recorded.
Straub’s Method:
A glass cannula is passed through the aorta and valves into the ventricle of heart, so that the solution is pumped up and down in the cannula with every beat.
A graph paper is attached behind the cannula to give an estimate of force of contracton of systole.
Every beat is recorded by attaching the tip of the ventricle through a thread to a lever.
Very widely used for the detection of small quantity of adrenaline.
Adrenaline increases the force of contraction of heart.
On Spinal
The spine of the cat is exposed.
Spine is destroyed by passing a stiff wire down the spinal canal.
This causes a precipitous fall in BP.
Then adrenaline is given in i.v route and observed for the rise in BP.
Bioassay of Noradrenaline
Preparation Activity assayed
BP of pithed cat Rise in BP
It can be assayed
By using aneasthetised dog also.
The procedure is same as the method used for bioassay of adrenaline.