chapter 4.7

Question 1

Drugs have two fundamentally different kinds of effects on synaptic transmission:

Answer 1

they facilitate it or they inhibit it.

Question 2

Agonists

Answer 2

drugs that facilitate the effect of a particular neurotransmitter.

Question 3

Antagonists

Answer 3

drugs that inhibit the effects of a particular neurotransmitter.

Question 4

Seven general steps are common to most neurotransmitters:

Answer 4

(1) synthesis of the neurotransmitter, (2) storage in vesicles, (3) breakdown in the cytoplasm of any neurotransmitter that leaks from the vesicles, (4) exocytosis, (5) inhibitory feedback via autoreceptors, (6) activation of postsynaptic receptors, and (7) deactivation.

Question 5

receptor blockers

Answer 5

some antagonistic drugs; bind to postsynaptic receptors without activating them and block the access of the usual neurotransmitter.

Question 6

Nicotinic receptors and muscarinic receptors

Answer 6

acetylcholine receptors. Are found in the CNS and the PNS. In the PNS, many nicotinic receptors occur at the junctions between motor neurons and muscle fibers, whereas many muscarinic receptors are located in the autonomic nervous system. Ionotropic and metabotropic, respectively.

Question 7

Atropine

Answer 7

main active ingredient of belladonna, is a receptor blocker that exerts its antagonist effect by binding to muscarinic receptors, thereby blocking the effects of acetylcholine on them. The pupil-dilating effects of atropine are mediated by its antagonist actions on muscarinic receptors in the ANS. The disruptive effects of large doses of atropine on memory is mediated by its antagonistic effect on muscarinic receptors in the CNS.

Question 8

Curare

Answer 8

receptor blocker at cholinergic synapses, but it acts at nicotinic receptors. By binding to nicotinic receptors, curare locks transmission at neuromuscular junctions, thus paralyzing its recipients and killing them by blocking their respiration.

Question 9

Botox

Answer 9

neurotoxin released by a bacterium often found in spoiled food, is another nicotinic antagonist, but its mechanism of action is different: it blocks the release of acetylcholine at neuromuscular junctions and is thus a deadly poison.

Question 10

Opiate drugs

Answer 10

bind effectively to receptors in the brain. these receptors were generally found in the hypothalamus and other limbic areas, but they were most concentrated in the area of the brain stem around the cerebral aqueduct; this part of the brain stem is called the periaqueductal gray (PAG). Microinjection of morphine, or even electrical stimulation, of the PAG produces strong analgesia.

Question 11

Endogenous

Answer 11

opioids occurring naturally within the body. All are neuropeptides and their receptors are metabotropic.

Question 12

Enkephalins

Answer 12

endogenous; meaning “in the head.”

Question 13

Endorphins

Answer 13

endogenous.

Question 14

Schizophrenia

Answer 14

caused by excessive activity at dopamine synapses. A particular dopamine receptor; D2 receptor, plays a key role and drugs that most effectively block it are the most effective antischizophrenia drugs.