6. Significance Of Signal Transduction Mechanisms In The Effects Of Drugs. Tachyphylaxis And Tolerance To Drugs

Front 1

What is the main difference between ionotropic and metabotropic receptors with regards to time?

Back 1

The signal transduction of ionotropic receptors is many times faster than that of metabotropic receptors.

Front 2

Name some ionotropic receptors.

Back 2

Nicotinic acetylcholine receptors, GABA-A receptor, 5-HT3 receptor

Front 3

Which enzyme does Gs-protein act on and how does it change its activity?

Back 3

Gs stimulates adenylyl cyclase

Front 4

Which enzyme does Gi-protein act on and how does it change its activity?

Back 4

Gi inhibits adenylyl cyclase

Front 5

Which enzyme does Gq-protein act on and how does it change its activity?

Back 5

Gq stimulates phospholipase C

Front 6

Name some Gs-protein coupled receptors

Back 6

Adrenergic β1 and β2 receptors, Dopamine D1 receptor, Histamine H2 receptor

Front 7

Name some Gi-protein coupled receptors

Back 7

Adrenergic α2 receptor, Dopamine D2 receptor, Muscarinic type 2 receptor

Front 8

Name some Gq-protein coupled receptors

Back 8

Adrenergic α1 receptor, Histamine H1 receptor, Muscarinic type 1 and 3 receptors

Front 9

Name some mechanisms in the body which are mediated by adenylyl cyclase and increased cAMP levels.

Back 9

Smooth muscle relaxation, cardiac muscle contraction, increase of neuronal excitability, increase of gastric acid secretion

Front 10

Name some mechanisms in the body which are mediated by phospholipase C and increased DAG and IP3 levels

Back 10

Smooth muscle contraction, cardiac muscle contraction, endothelium-dependent vasodilation, eurotransmitter release, hormone secretion

Front 11

Which enzyme does NO act on?

Back 11

Guanylyl cyclase

Front 12

Name some enzyme-linked receptors

Back 12

Insulin receptor, growth factor receptors, cytokine receptors

Front 13

Name some types of enzyme-linked receptors

Back 13

Tyrosine kinase-linked (receptor tyrosine kinase), guanylate cyclase-linked, tyrosine-phosphatase-linked or serine/threonine kinase-linked.

Front 14

Name some intracellular receptors.

Back 14

Steroid hormone receptors, thyroid hormone receptors, vitamin D receptors and retinoid receptors.

Front 15

Name some drugs which bind to intracellular receptors?

Back 15

Retinoids and glucocorticoids

Front 16

What can you say about the speed of the signal transduction of intracellular receptors?

Back 16

It's very slow.

Front 17

What is tachyphylaxis?

Back 17

Tachyphylaxis is an acute phenomenon that causes a drug to lose its effect on a patient in the short-term, like in minutes or hours.

Front 18

Which mechanisms can explain tachyphylaxis?

Back 18

Receptor desensitization

The number of available receptors is reduced because other ligands occupy them

An endogenous compound necessary for the drug action is depleted

Front 19

Name some drugs which often cause tachyphylaxis.

Back 19

Organic nitrates

Front 20

What is tolerance?

Back 20

Tolerance is a chronic phenomenon that causes a drug to lose its effect in the long-term, like in days or weeks.

Front 21

Which mechanisms can explain tolerance?

Back 21

The number of receptors is downregulated Enzymes that metabolize the drug are stimulated

The body counteracts the drug effects by using other mechanisms

Drugs are more actively “pumped out” of the cells

The body starts producing antibodies against the drug

Front 22

Name some drugs which often cause tolerance development.

Back 22

Ethanol, opioids, psychoactive drugs.

Front 23

What is the mechanism of desensitization of receptors?

Back 23

Receptor activation causes kinases to phosphorylate the of receptor. This phosphorylation activates a protein called Arrestin, which causes the receptor to be internalized.