Requirement
Software & personal computer.
Theory
Acetylcholine
Acetylcholine is a major neurohumoral transmitter at autonomic, somatic as well as central site. Acetylcholine is synthesized locally in the cholinergic nerve endings.
Ach hyperpolarizes the SA nodal cells and decreases their rate of diastolic depolarization. As a result, rate of impulse generation is reduced – bradycardia or even cardiac arrest may occur. The cardiac muscarinic receptors are of the M2 subtype.
Ach hyperpolarizes the SA nodal cells and decreases their rate of diastolic depolarization. As a result, rate of impulse generation is reduced – bradycardia or even cardiac arrest may occur. The cardiac muscarinic receptors are of the M2 subtype.
Adrenaline
Adrenaline increases heart rate by increasing the slope of slow diastolic depolarization of cells in the SA node. All cardiac actions are predominantly 𝛽1 receptor mediated. When BP rises markedly, reflex bradycardia occurs due to stimulation of vagus – this is the usual response seen when NA is injected i.v.
Procedure
- Isolation of frog heart is done as per the routine procedure.
- Inject the drugs and observe the following parameters.
- a. Heart rate
- b.Tone
- c. Force of contraction
Tabulate the data
S.No.
|
Name of Drug
|
Dose(mcg)
|
Concentration
|
1.
|
Epinephrine(Adrenaline)
|
2
|
10 mcg/ml
|
2.
|
Acetylcholine
|
2
|
10 mg/ml
|
Volume of above solutions to be injected = 0.2 ml; mcg = micrograms
Result - We studied the effect of acetylcholine and adrenaline on frog’s heart.
Acetylcholine decreases heart rate and also decreases contractibility of heart tissues.
Adrenaline increases the contraction of cardiac tissue and also increases the heart rate & tone.
0 comments:
Post a Comment