[PCOL-SEMIS-01-PT6] AUTACOIDS: HISTAMINE AGONISTS AND ANTAGONISTS

THIS FLASHCARDS IS ABOUT [PCOL] AUTACOIDS.

1. Histamine (synthetic)

2. Pulmonary bronchoconstriction

This (1) histamine is no longer in use (obsolete use) but this is used in pulmonary (challenge) function tests before; it is a provocative test causing (2)__________.

Supplemental Info Only

Synthetic histamine is intentionally injected to the patient to provoke organ or induce bronchoconstriction to test how well the lungs function.

Gastric Acid Secretion

Histamine (synthetic) is used to determine the adequacy (how much) of?

H1 receptors

Pulmonary (challenge) binds to what receptors?

H2 receptors

Adequacy of gastric acid secretion binds to what receptors?

Serc®

Betahistine is marketed by what brand name?

1. H1-receptor agonists

2. H3-receptor antagonists

Betahistine (Serc®)

1. ________ agonists

2. ________ antagonists

Bronchoconstriction

(Increase of capillary permeability)

The mechanism of action of Betahistine (Serc®) is the activation of H1 receptors, resulting to?

Vertigo

(By blocking presynaptic H3 receptors, it increases the release of histamine, which improves vestibular function and blood flow in the inner ear)

Betahistine is used in the management of ________ partly because it acts as an H3-receptor antagonist.

Supplemental Info Only

Betahistine also has weak H1 agonist activity, contributing to vasodilation in the inner ear, which further helps reduce vertigo symptoms.

Loss of Balance

Vertigo is associated with __________ because of the irritation (constriction of blood vessels) of inner ear.

Inner Ear

This is important in the postural balance.

Vasodilation

(Increase of blood flow in the inner ear; restoring balance, managing vertigo)

Betahistine’s (Serc®) effect once it binds is?

• First Generation

• Second Generation

What are the (2) Classifications of H1-Antagonists (Blockers)?

1. Highly lipophilic

2. Sedation

First Generation H1 Blockers is highly (1)_____; affects the CNS causing (2)_____ because they can cross the blood brain barrier.

Classical/Sedating

First Generation H1 Blockers is also known as?

• Ethanolamines

• Ethylenediamine

First Generation H1 Blockers has a (+) atropine-like effects, specifically the (2)?

Anticholinergic Effect

(e.g., constipation, urinary retention, and mydriasis)

Atropine-like effects refers to what effect?

1. Piperazines

2. Piperidines

Second Generation H1 Blockers are:

• Less sedating (ex. 1._____)

• Non-sedating (ex. 2._____)