catecholamines classification,mode of action,synthesis,types of recepetors,pharmacological actions of drugs and uses

1. Adrenergic
system(catecholamines)
Adrenergic system or Adrenergic nervous system (ANS) is a group of
organs and nerves in which adrenaline (epinephrine) and/or
noradrenaline (norepinephrine) act as neurotransmitters. ANS is
counted as one of the main neurohormonal systems that regulate
cardiovascular function, including smooth muscle tone.

2. • There are closely related Endogenous catecholamines :
• Adrenaline include increasing the heart rate, increasing blood
pressure, expanding the air passages of the lungs, enlarging the pupil
in the eye , redistributing blood to the muscles and altering the
body’s metabolism, so as to maximise blood glucose levels
• Noradrenaline : act as transmitter at Postganglionic sympathetic sites
except hair follicles and sweat glands and Some vasodilator fibres
• Dopamine : Major transmitter in basal ganglia ,limbic
system,CTZ,anterior pituitary etc…

3. Catecholamines synthesis

4. Receptors in adrenergic system

7. Adrenergic Neurotransmission. …

8. Classification

9. Pharmacological actions of Catecholamines
• Effects on Herat : The catecholamines increases all four effects of heart
activity. Increase of the inotropic effect causes contractility of the cardiac
muscle increasing the cardiac output by increasing the stroke volume. …
The catecholamines alter the blood pressure by altering the vascular
resistance.
• Effects on blood vessels :The catecholamines alter the blood pressure by
altering the vascular resistance. Control of the vascular resistance is
achieved through vasoconstriction and vasodilation.
• Effects on Respiration :The results of this study indicate that at control
vascular tone the catecholamines norepinephrine and epinephrine increase
pulmonary vascular resistance large doses of adrenaline produces
pulmonary oedema

10. • Effects on Eye :effectiveness of catecholamines in lowering ocular
tension produces mydriasis effect
• GIT : Gut relaxation.. Through activation. Of alpha and beta receptors
• Vascular resistance, and a decrease in overall blood flow to the
intestines.
• Bladder .Dtressur is relaxed act on beta.Trigone is constructed act on
alpha
• Uterus .Both contraction and relaxation By alpha and beta

11. • Skeletal muscle.An increase in phosphorylase a levels preceded the
tissue glycogen loss in both heart and skeletal muscle after
catecholamine administration. … Increased or decreased tissue
catecholamine levels were without effect on cardiac phosphorylase a
values. Reserpine increased the cardiac glycogen content.
• CNS .Catecholamines, including dopamine and norepinephrine, are
the principal neurotransmitters that mediate a variety of the central
nervous system functions, such as motor control, cognition, emotion,
memory processing, and endocrine modulation.

12. • Metabolism ……Under physiologic conditions, infusing catecholamine
is associated with enhanced rates of aerobic glycolysis (resulting in
adenosine triphosphate production), glucose release (both from
glycogenolysis and gluconeogenesis), and inhibition of insulin-
mediated glycogenesis.

13. • Dopamine is primarily a dopamine receptor agonist; however, at
higher doses, dopamine activates α- and β-adrenergic receptors, too.
Dopamine is administered as a continuous intravenous infusion. … At
high doses, dopamine stimulates α-adrenergic receptors in the
vasculature.Dopamine increased pulse pressure, heart rate
• Dobutamine is a synthetic catecholamine that acts on alpha-1, beta-1
and beta-2 adrenergic receptors. In the heart, the stimulation of
these receptors produces a relatively strong, additive inotropic effect
and a relatively weak chronotropic effect.
• Ephedrine is a direct and indirect sympathomimetic amine. Ephedrine
activates adrenergic α and β-receptors as well as inhibiting
norepinephrine reuptake, and increasing the release of
norepinephrine from vesicles in nerve cells.

14. • Amphetamines can also block the reuptake of norepinephrine,
dopamine, and serotonin. Some amphetamines increase the release
of monoamines, such as serotonin and norepinephrine
• Phenylephrine is a selective α1-adrenergic receptor agonist that
increases blood pressure mainly by increasing systemic vascular
resistance, without an associated increase in myocardial contractility
• Isoxsuprine is a phenylethylamine derivative of epinephrine and has
α-adrenergic receptor antagonistic and β-adrenergic receptor
agonistic properties that result in relaxation of vascular smooth
muscle
• Pseudoephedrine is an orally active sympathomimetic amine exerting
its decongestant action by acting directly on α-adrenergic receptors in
the respiratory tract mucosa producing vasoconstriction resulting in
shrinkage of swollen nasal mucous membranes, reduction of tissue
hyperemia, edema, and nasal congestion

15. • Fenfluramine acts primarily as a serotonin releasing agent. It
increases the level of serotonin, a neurotransmitter that regulates
mood, appetite and other functions. Fenfluramine causes the release
of serotonin by disrupting vesicular storage of the neurotransmitter,
and reversing serotonin transporter function.
• Anorexiants are drugs that act on the brain to suppress appetite. They
have a stimulant effect on the hypothalamic and limbic regions, which
control satiety. Anorexiants are used as therapy for obesity.
• Sibutramine is a synthetic noradrenaline, dopamine, and serotonin
reuptake inhibitor used for the treatment of obesity. FDA and
European Medicines Agency banned it because of its cardiovascular
risk