cox-2 inhibitors types of prostaglandins and their effects

2. • The prostaglandins are a group of lipids made
at sites of tissue damage or infection that are
involved in dealing with injury and illness.
• They control processes such as inflammation,
blood flow, the formation of blood clots and the
induction of labour.
• Prostaglandins are very short-lived and are
broken down quickly by the body.

3. • Unlike most hormones, the prostaglandins are not
secreted from a gland to be carried in the bloodstream
and work on specific areas around the body. Instead,
they are made by a chemical reaction at the site where
they are needed and can be made in nearly all the
organs in the body. Prostaglandins are part of the body’s
way of dealing with injury and illness
• They only carry out their actions in the immediate vicinity
of where they are produced; this helps to regulate and
limit their actions.

4. • Prostaglandin D2
• prostaglandin E2
• prostaglandin F2
• prostaglandin I2 (which is also known as
prostacyclin)
• A closely related lipid called thromboxane

7. • The chemical reaction that makes the prostaglandins involves
several steps;
• the first step is carried out by an enzyme called
cyclooxygenase.
• There are two main types of this enzyme: cyclooxygenase-1
and cyclooxygenase-2.
• . COX-1 is also called as constitutive enzyme because it is
produced by a cell under all types of physiological
conditionsCOX-1 enzymes are protective in nature and
therefore are useful for the body.
• On the other hand COX-2 is an inducible enzyme as it is
produced under certain specific conditions like
inflammation.cyclooxygenase-2 is activated and produces
extra prostaglandins, which helps the body to respond to the
injury.

11. • Five major types of prostanoid receptors have been
designated
• All prostanoid receptors are G-protein coupled receptors
which utilize the IP3/ DAG or cAMP transducer mechanisms
• The prostanoid receptors are:
• DP
• Has greatest affinity for PGD2, but PGE2 also acts on it
• activation increases cAMP which
• inhibits platelet aggregation.
• vasodilatation
• Relaxation of GI & uterine muscles

12. i. EP
Has greatest affinity for PGE2
• It has been subdivided into
• EP1 which causes smooth muscle contraction through
IP3/DAG pathway
• Broncho constriction • GI tract smooth muscle contraction
• Acting on EP 2 receptors smooth muscle relaxation by
increasing cAMP
• • Broncho dilatation • GI tract smooth muscle relaxation •
Vasodilatation
• Acting on EP 3 receptors
• Decrease gastric acid secretion • Increase gastric mucus
secretion • Uterus contraction (when pregnant) • GI tract
smooth muscle contraction

13.  FP Has greatest affinity for PGF2α
• The most prominent effect of activation of this receptor is
smooth muscle contraction
• Myometrial contraction • Broncho constriction •
Vasodilatation • Ocular inflammation mediated through
IP3/DAG formation.
 IP Has greatest affinity for PGI2
 It functions by activating adenylyl cyclase in
 platelets (inhibiting aggregation) and smooth muscles
(relaxation).
 TP Has greatest affinity for TXA2; It utilizes IP3/DAG as
second messengers which mediate platelet aggregation
and smooth muscle contraction.

14. • High levels of prostaglandins are produced in response
to injury or infection and cause inflammation, which is
associated with the symptoms of :
• redness,
• swelling,
• pain and fever.
• This is an important part of the body’s normal healing
process.

15. • Prostaglandins are made at sites of tissue damage or
infection, where they cause inflammation, pain and fever
(as part of the healing process).
• When a blood vessel is injured, a prostaglandin called
thromboxane stimulates the formation of a blood clot to
try to heal the damage; it also causes the muscle in the
blood vessel wall to contract (causing the blood vessel to
narrow) to try to prevent blood loss.

16. • Another prostaglandin called prostacyclin has the
opposite effect to thromboxane, reducing blood clotting
and removing any clots that are no longer needed; it also
causes the muscle in the blood vessel wall to relax, so
that the vessel dilates.

17. • Misoprostol
• a PGE 1 derivative is a cytoprotective prostaglandin
• used in preventing peptic ulcer
• PGE 2 and PGF 2 are used in obstetrics to induce
labor
• Latanoprost and several similar compounds are
topically active PGF 2α derivatives used in
ophthalmology to treat open-angle glaucoma

18. • Prostacyclin used clinically to treat pulmonary
hypertension and portopulmonary hypertension.
• Clinical importance of product of arachidonate series
Thromboxane (TXA 2 )
• has undesirable properties (aggregation of platelets,
vasoconstriction).
• TXA 2 –receptor antagonists and synthesis inhibitors
have been developed for cardiovascular indications
• nt’d….