49).ADRENALINE

[Editor]

a) is formed by the methylation of noradrenaline
b) dilates the coronary arterioles
c) does not affect liver phosphorylase activity
d) decreases cardiac output by reflex bradycardia
e) has no action on free fatty acid metabolism

[Editor]

ttftf
Phenolethanolamine-N-methyl transferase is the enzyme that methylates noradrenaline to adrenaline and is found only in the brain and adrenal medulla.Metabolic vasodilatation outweighs the increased vasoconstrictor activity and so blood flow increases in the coronary circulation. This metabolic overriding of vasoconstriction ensures that any generalised activation of sympathetic system does not imperil blood flow to the heart.Adrenaline, secreted in times of stress, reinforces the coronary hyperaemia by preferentially activation Beta 2 receptors in the coronaries causing vasodilatation.Both adrenaline and noradrenaline cause glycogenolysis increasing the blood sugar by action on Beta receptors ,increasing CAMP by activation of phosphorylase and thereby increasing the Calcium concentration.Adrenaline increases cardiac output,increases heart rate and BP.It causes peripheral vasodilatation and decrease in peripheral resistance,widening the pulse pressure as the systolic increases while the diastolic decreases.In adipose tissues adrenaline stimulates the adenyl cyclase in the Beta receptors,which increase the cyclic AMP and via the protein kinases the inactive lipase is converted to active lipases,which in turn converts triglycerides to FFA and glycerol.

[Eloise]

Adrenaline does not reduce cardiac output.