Pharm Intro

Question 1

Where do 5HT neurons from rostral raphe project to?

Answer 1

Ascend to cerebral cortex, limbic regions, and basal ganglia

Question 2

Where do 5HT neurons from caudal raphe project to?

Answer 2

Terminate in medulla or descend to spinal cord

Question 3

What receptors does 5HT act on?

Answer 3

Both ion channels and G proteins. May be excitatory or inhibitory.

Question 4

What does 5HT do to blood vessels?

Answer 4

Vasoconstriction

Question 5

How does LSD affect 5HT?

Answer 5

Antagonizes. Structure is similar.

Question 6

4 major DA pathways

Answer 6

• Substantia nigra to caudate/putamen
• Ventral tegmentum to mesolimbic forebrain
• Ventral tegmentum to frontal cortex
• Tuberoinfundibular system (arcuate nucleus to median eminence)

Question 7

What types of receptors does DA act on?

Answer 7

DA acts via 5 different G proteins

D1 and D5 activate adenylyl cyclase. D2-4 inhibit adenylyl cyclase.

Question 8

How does DA effect prolactin secretion?

Answer 8

Inhibits prolactin secretion?

Question 9

2 main NE pathways

Answer 9

• Axons from locus coeruleus project to frontal cortex, thalamus, hypothalamus, limbic system, and cerebellum.
• NE axons from caudal raphe nuclei ascend to amygdala and midbrain.

Question 10

NE receptors

Answer 10

NE acts via G protein coupled adrenergic receptors. A1 and B1 are excitatory. A2 and B2 are inhibitory.

Question 11

From where is histamine released?
Characteristic of neurons
Function
3 different receptor subtypes

Answer 11

• Histamine pathways originate in the tuberomamillary nucleus.
• Neurons are pacemakers.
• Aids in arousal, analgesia, locomotion, learning, and memory.
• 3 different receptor subtypes.
• H1 acts via Gq, excitatory
• H2 acts via Gs, usually excitatory
• H3 autoreceptors aid in negative feedback, inhibiting histamine synthesis / release.

Question 12

Mechanism of antihistamines

Answer 12

Inverse agonist

Question 13

3 main glutamate pathways

Answer 13

• Cortico-cortical pathways
• Between thalamus and cortex
• Extrapyramidal pathway (b/w cortex and striatum)

Question 14

Glutamate receptors

Answer 14

Acts via ion channels (NMDA, KA, AMPA) and G proteins (mGLU1-8)

Question 15

GABA receptors

Answer 15

• Acts via ion channels (GABAa) and G proteins (GABAb).
• Drugs effect GABAa more than GABAb.
• GABAa receptor is a Cl channel (hyperpolarizing). 2 binding sites for GABA. Pentameric. Benzos and barbiturates bind to GABA receptors to inhibit seizures.

Question 16

Function of glycine

Answer 16

Inhibitory NT acting via interneurons of SC and brain stem. Cl ion channel.

Question 17

Synthesis / breakdown of GABA

Answer 17

• Glutamic acid decarboxylase converts glutamate to GABA, and vice versa.
• GABA transaminase breaks GABA down to succinic semialdehyde. Blocking this enzyme increases GABA levels.

Question 18

3 groups of Ach neurons

Answer 18

• Basal forebrain cholinergic complex
• Pontomesencephalotegmental cholinergic complex
• Ach is also released from interneurons in the striatum.

Question 19

Ach receptors

Answer 19

• Ach acts on G protein coupled M1 and M2 muscarinic receptors.
• M1 receptors are excitatory via ↓ K+ conductance, ↑ IP3 and DAG production
• M2 receptors are inhibitory via ↑ K+ conductance, ↓ cAMP production
• Brain also contains excitatory nicotinic receptors.

Question 20

Peptide hormones
•Cholecystokinin
•Neuropeptide Y
•Orexin
•Hypothalamic and pituitary hormones
•Opioids
•Substance P

Answer 20

• Cholecystokinin: satiety
• Neuropeptide Y: stimulates feeding behavior
• Orexin: stimulates feeding behavior and wakefulness
• Hypothalamic and pituitary hormones: oxytocin and vasopressin (ADH)
• Opioids (endorphins, enkephalins, dynorphin): pain perception
• Substance P: pain perception