Pharmacology I - Histamine_Serotonin_&_Antagonis

Front 1

What are chemical mediators, play a significant role in physiologic or pathophysiologic responses to injury. Generally act locally, termed local hormones, and are short-lived?

Examples?

Back 1

autocoids

Short-lived; rapidly degraded
Ex. histamine, serotonin

Front 2

What is a biogenic amine and an endogenous mediator of cellular injury. Mainly involved in inflammation, anaphylaxis, allergies, and drug reactions, and regulates gastric acid secretion?

Back 2

histamine

Front 3

Whic histamine receptor modulates neurotransmitter release in CNS?

Back 3

histamine receptor type 3

Front 4

Which histamine receptor mediates smooth muscle contraction, relaxes arterioles, and reduces peripheral resistance and blood pressure?

Back 4

histamine receptor type 1 (H1)

Front 5

Which histamine receptor stimuates gastric acid secretion?

Back 5

gastric acid secretion? histamine receptor type 2

Front 6

Histamine is synthesized from the decarboxylation of what?

Back 6

amino acid histadine by histidine decarboxylase enzyme

Front 7

2 types of Histamine stores?
Where is each found?

Back 7

1. Mast cell pool (mast cells and basophils)
*Key role in inflammation, allergy/shock, drug reactions/ hypersensitivity

2. Non-mast cell pool (GIT, CNS, dermis)

Front 8

Where is histamine slowly synthesized and stored tenaciously in secretory granules?

Back 8

mast cell pool

Front 9

Which histamine store participates in inflammatory responses, shock, adverse drug reactions, hypersensitivity allergic reactions and cellular injury?

Back 9

mast cell pool (mast cells and basophils)

Front 10

Which store synthesize/release histamine continuously?
Where?

Back 10

Non-mast cell pool (GIT, CNS, dermis)
* Continuous synthesis and release
Ex. histamine induced gastric acid secretion

Front 11

What happens in the non-mast cell pool?

Back 11

histamine is synthesized/released continuously; the turn-over rate is rapid. in gastic mucosa, histamine produces local hormone action in gastric acid secretion

Front 12

Which store synthesize/release histamine slowly?

Back 12

Mast cell pool (mast cells and basophils)
* Synthesized slowly

Front 13

How can physical injury cause histamine release.

Back 13

heat, cold, trauma, can cause cell damage, releasing histamine from mast cells

Front 14

antibody of a specialized immunoglobulin class (IgE) which attaches to tissue cells of the same species from which it is derived, and which interacts with its antigen to induce the release of histamine and other vasoactive amines. A form of cytotropic antibody, it is present in the serum of naturally hypersensitive individuals and can confer specific immediate (type I) hypersensitivity in nonreactive individuals.

Back 14

Reagin antibody

Front 15

In an anaphylaxis-allergy, what induces histamine release?

Back 15

interaction of antigen and cell bound reaginic, Ab increases cells permeability to Ca ions, increase in Ca ion induces histamine release

Front 16

What is the role of histamine in anaphylaxis and allergy?

Back 16

induces vasodilation, itching, smooth muscle contraction, and edema. in humans histamine produces flushing of the skin, burning and itching sensations

Front 17

What is the role of histamine in gastric secretions?
(mention which receptor involve, what secrete or not secreted, etc.)

Back 17

histamine acts on H2 receptors of gastric mucosa and stimulates HCL secretion

Front 18

Histamine release in the CNS is involved in what?

Back 18

the emetic response (motion sickness or nausea) that may be directed either through the chemoreceptor zone (like if smell something nasty) or via vestibular stimulation or directly to the emetic center of the brain

Front 19

What is histamines role in microcirculation?

Back 19

histamine relaxes arterioles and increases capillary permeability

Front 20

What effects are produced by histamine when administered IV?

Back 20

smooth muscle contractions, hypotension, increase gastric secretion, dermal reaction

Front 21

What does histamine do in rabbits?

Back 21

is a pressor agent, where vasoconstriction is more prominent

Front 22

After an intradermal injection of histamine, what characteristic is produced in humans?

Back 22

wheal and flare reaction

Front 23

What is the difference in vasodilator response in H1 and H2?

Back 23

H1 occurs at low doses, is rapid onset and brief duration, H2 occurs at larger doses, is slower in onset, but lasts longer

Front 24

Histamine causes contraction of bronchial smooth muscles in what animals?

Back 24

guinea pig, rabbit, dog, goat, calf, pig, horse, and human

Front 25

Histamine induces relaxation of respiratory smooth muscles in what animals?

Back 25

cat and sheep

Front 26

Vasodilator response is mediated through ________ which activated nitric oxide synthase and release of endothelium derived nitric oxide.

Back 26

endothelial H1 receptors

Front 27

What acts through G-protein coupled adenylyl cyclase activation and increases synthesis of cAMP, second messenger for activation of protein kinase A

Back 27

H2 receptors

Front 28

What enzyme converts Histidine amino acid to histamine?

Back 28

Histidine decarboxylase converts Histidine to histamine

Front 29

What acts through G-protein coupled adenylyl cyclase activation and increases synthesis of cAMP, second messenger for activation of protein kinase A

Back 29

H2 receptors

Front 30

On parenteral administration, histamine is ________ absorped, but poorly absorped through oral route?

Back 30

completely

Front 31

What is a therapeutic use of histamine agonist, histamine phosphate?

Back 31

test agent for achlorhydria, pheochromocytoma

Front 32

What is a therapeutic use of histamine agonist, betazole?

Back 32

has 10-fold selective activity for stimulation of gastric acid production over vasodilation

Front 33

What are examples of first generations antihistamines?

Back 33

chlorpheniramine, diphenhydramine, hydroxyzine, dimenhydrinate, meclizine, promethazine, cyproheptadine

Front 34

What is the action of first generation antihistamines?

Back 34

unionized as physiological pH and easily cross the blood brain barrier, thus produces sedation

Front 35

What are examples of second generation antihistamines?

Back 35

astemizole., cetrizine, desloratadine, fexofenadine, loratadine, terfenadine,

Front 36

What is the action of first generation antihistamines?

Back 36

lack antimuscarinic properties and do not cross BBB, lacks CNS side effects such as sedation

Front 37

What drug is well absorbed with a half life or 24 hours. IV admin is recommended only in acute anaphylaxis condition. IM route is preferred than IV route. Topical route is used for treating skin infections.

Back 37

Chlorpheniramine

Front 38

effects produced by antihistamines on bronchiolar and intestinal smooth muscle?

Back 38

relaxation of bronchiolar and intestinal smooth muscle

Front 39

wheal

Back 39

small swelling on skin, as from insect bite, that usually itches or burns.

Front 40

wheal-and-flare reaction

Back 40

The characteristic immediate reaction to injected allergen in skin test, in which irregular blanched wheal appears, surrounded by area of redness. Also called wheal-and-erythema reaction.

Front 41

What are some effects produced by antihistamines on formation of edema and wheals in cell injuries?

Back 41

block formation of edema and wheals in cell injuries, inhibition of itch sensation, anti-inflammatory response

Front 42

What are some of the effects produced by antihistamines on motion sickness?

Back 42

antimotion sickness

Front 43

Increase in cAMP – ____ histamine release

Back 43

Increase in cAMP – suppresses histamine release

Front 44

So activation of adenylyl cyclase (Epinephrine) leads to ___?

Back 44

So activation of adenylyl cyclase (Epinephrine) and inhibition of phosphodiesterase enzyme – decreases histamine release.

Front 45

treatment of allergic patients, allergic reactions to drugs, anaphylaxis, treatment of respiratory disorders

Back 45

some therapeutic effects of antihistamines

Front 46

What are common conditions that antihistamines treat?

Back 46

urticaria (hives), dermatitis, eczema, otitis, insect stings, laminitis, periodic opthalmia (inflammation of the eye), gangrenous mastitis and metritis (bovine), gut edema (pigs)

Front 47

What are some side effects of antihistamines?

Back 47

CNS depression, CNS excitement, Antimuscarinic effects, intestinal disorders, teratogenic effects, drug intolerance

Front 48

What are some examples of antihistamines?

Back 48

chlorpheniramine, diphenhydramine, clemastine, hydroxyzine, trimeprazine

Front 49

What inhibits the release of histamine and other autocoids from the mast cells, facilitate opening of chloride ion channel, hyperpolarizing cells, does not inhibit H1 and H2 receptors?

Back 49

cromolyn sodium

Front 50

Does H2 mediated vasodilation occur at large doses or small doses?

Back 50

H2 vasodilation at LARGE doses
slow onset; long duration

Front 51

Does H1 mediated vasodilation occur at large doses or small doses?

Back 51

H1 mediated
at LOW doses of histamine

Front 52

Histamine effects on respiratory/bronchial smooth muscle in cat and sheep?

Back 52

RELAXATION of respiratory smooth muscle in cat and sheep

Front 53

Histamine effects on bronchial Smooth muscle in goat, calf, pig, horse, people

Back 53

Contraction of bronchial smooth muscle (guinea pig, rabbit, dog, goat, calf, pig, horse, human)
WTF???

Front 54

Histamine effects on intestinal and uterine smooth muscle?

Back 54

Contraction of intestinal muscle and uterine smooth muscle

Front 55

Histamine effects: exocrine gland

Back 55

Histamine effects: exocrine gland
* Gastric HCL secretion
Salivary, pancreatic, bronchial and lacrimal secretion

Front 56

Which receptor Acts through Gq – activates phospholipase C enzyme

Back 56

H1 receptor: Acts through Gq – activates phospholipase C enzyme

Front 57

What effect do H1 and activation of phospholipase C enzyme have on inositol tri phosphate and intracellular calcium?

Back 57

activates phospholipase C enzyme -> Increases inositol tri phosphate and intracellular calcium

Front 58

type receptor that releases nitric oxide through nitric oxide synthase?

Back 58

Endothelial H1 receptors

Front 59

Which receptor Acts through Gs – activates adenylyl cyclase enzyme

Back 59

H2 receptor:
Acts through Gs – activates adenylyl cyclase enzyme

Front 60

H2 receptor:
Acts through Gs – activates adenylyl cyclase enzyme which ____ intracellular cAMP (protein kinase activation)

Back 60

H2 receptor: Acts through Gs – activates adenylyl cyclase enzyme
---> Increases intracellular cAMP (protein kinase activation)

Front 61

T/F Parenteral administration of antihistamine – completely absorbed

Back 61

TRUE

Front 62

are antihistamine metabolized quick or slow?

Back 62

Rapid metabolism

Front 63

H2 receptor agonist

Back 63

Betazole = H2 histamine agonist

Front 64

Test agent for achlorhydria

Back 64

Histamine phosphate

Front 65

ways in which histamine metabolized?

Back 65

Metabolism - methylation and oxidation

Front 66

which type of antihistamine do not cause CNS SEDATION

Back 66

Second generation antihistamines

Front 67

The enzyme tryptophan hydroxylase converts tryptophan to 5-hydroxytryptophan, which in turn acted upon by the enzyme L-aromatic acid decarboxylase to from what?

Back 67

Serotonin (5-hydroxytryptamine, 5-HT)

Front 68

Where is serotonin present in high concentrations?

Back 68

platelets, enterochromaffin cells and myenteric plexus of GIT and CNS, bananas, pinapples, and plums

Front 69

What is serotonins physiological role in GIT?

Back 69

regulates motility

Front 70

What is serotonins physiological role in CNS?

Back 70

acts as neurotransmitter

Front 71

How is serotonin metabolized and excreted?

Back 71

undergoes oxidative deamination by monoamine oxidase enzyme, endproducts are excreted in urine

Front 72

What are drugs known as that inhibit serotonin (5HT) uptake?

Back 72

selective serotonin reuptake inhibitors, used to treat depression and other neurological disorders

Front 73

How many types of serotonin receptors are there?

Back 73

7 types of G-protein coupled receptor complexes

Front 74

Rapid IV injection of serotonin produced triphasic response as follows:

Back 74

initial fall of systemic arterial pressure with bradycardia, short period of pressor effect, prolonged fall in systemic BP

Front 75

What are pharmacological effects of serotonin?

Back 75

decreases pulmonary arterial pressure, causes contraction of smooth muscles of bronchi and intestine, increases GIT motility

Front 76

What are serotonin agonists in nature?

Back 76

ergot alkaloids (ergotamine, ergonovine, ergocristine) that come from claviceps purpurea

* ergot alkaloids refers to a group of fungi of the genus Claviceps

Front 77

What is the therapeutic use of ergonovine?

Back 77

control postpartum haemorrhage and induce uterine involution

Front 78

What is a serotonin agonist, has a theraputic use against gastric stasis, reflux esophagitis, constipation and megacolon in cats, but can cause diarrhea and colic?

Back 78

Cisapride

Front 79

What is a serotonin agonist, has a therapeutic use against vomiting disorders, reflux esophagitis, gastric stasis/hypomotility, but can cause a change in mood or behaviour and constipation?

Back 79

Metclopramide

Front 80

What is a serotonin antagonist, is appetitie stimulant in cats, treats feline asthman and photic head shaking in horses, however can cause polyphagia, sedation, and anorexia?

Back 80

Cyproheptadine

Front 81

What is a serotonin antagonist, has a therapeutic use against ergovaline-induced severe vasoconstriction, and reduces intraocular pressure in glaucoma?

Back 81

ketanserin

Front 82

What drug is a serotonin antagonist, has a therapeutic use against migraines in humans and carcinoid syndrome?

Back 82

methysergide