Opiates

Question 1

Effects of opiates

Answer 1

analgesic, antitussive, sedative, gastro-intestinal muscle relaxant

Question 2

Narcotic

Answer 2

classic term for the opiates and opiate-like drugs; comes from Greek word Narcotikos = to make sleep or to numb.

Question 3

Heroin is metabolized to morphine in the _____.

Answer 3

Heroin is metabolized to morphine in the brain

Heroin (with two acetyl groups) is a lot more fat soluble that morphine, so it takes a smaller dose.

Question 4

Fentanyl

Answer 4

a true synthetic opiate that is about 100X as powerful as morphine.

Question 5

Naloxone/naltrexone

Answer 5

critical drugs, direct antagonists for opiate receptors. Allows blockade of opiate effects (used in EMT cocktail)

Question 6

Metabolism of opiates:

Answer 6

all opiates are metabolized by liver and excreted by the kidney in urine

Question 7

Opiate Pharmacodynamics

Answer 7

all opiates are direct agonists that work at a group of receptors in the brain called opiate receptors.

Question 8

Opiate receptors

Answer 8

all are indirect gating; mediate changes in ion conductances that decrease excitability (K+) or synaptic transmission (Ca2+)

Question 9

Potassium shunt

Answer 9

Potassium shunt: as sodium goes in, potassium goes out.

Question 10

3 kinds of opiate receptors

Answer 10

(postsynaptic and presynaptic potassium shunts)

Question 11

Where do opiates bind?

Answer 11

Brainstem, thalamus, hippocampus

Question 12

Classic opiate receptor

Answer 12

Mu receptor, most sensitive to morphine and heroin – widespread distribution; underlie euphoric, brain & spinal analgesic, sedative (dorsal horns have a lot of these receptors); GI motility effects

Question 13

Raphe nuclei:

Answer 13

brain’s main source of serotonin

Question 14

Delta opiate receptors:

Answer 14

more sensitive to enkephalins, one of the endogenous opiates. Involved in spinal mechanisms of analgesia

Question 15

Kappa opiate receptors:

Answer 15

most sensitive to dynorphin. Most common in spinal cord and brainstem. Involved in spinal analgesia and sedation – significantly, kappa opiate receptors have analgesic effects without rewarding properties of mu opiates. High in the thalamus, LC, and raphe nucleus.

Question 16

Nocioceptive neurons, where are they first modulated?

Answer 16

the modulation of pain, but not touch, begins as soon as you hit the CNS at the dorsal root ganglia

Question 17

Dorsal root ganglia synapse is inhibited by ____

Answer 17

inhibited by 5HT, endogenous opiates, and touch neurons.

Question 18

Gylcine

Answer 18

in the spinal cord is like GABA in the brain – glycine is the main spinal inhibitor

Question 19

Opiate tolerance:

Answer 19

develops to most effects; reason why dose must be increased to maintain an analgesic or reinforcing effect of the drug. Generally requires frequent administration, seems to involve enhanced activity of second messengers associated with opiate receptors