Intro to CNS Pharmacology

Question 1

how is GABA (γ-aminobutyric acid) synthesized?

Answer 1

Synthesis intertwined with the synthesis of glutamate via the GABA shunt - formed from Glutamate via GAD (glutamic acid decarboxylase)

Question 2

Action of GABA at synapse terminated by reuptake into the presynaptic nerve terminal and surrounding glial cells; GABA transporter similar to ________

Answer 2

monoamine reuptake transporters

Question 3

what is the  transduction mechanisms
for GABA(A) receptors

Answer 3

Opens ligand-gated Cl- channel -> decreases neuronal excitability (IPSPs) [ionotropic]

Question 4

what is the transduction mechanism for GABA(B) receptors

Answer 4

Gi/o -> inhibit adenylyl cyclase -> decrease Ca++ conductance -> open K+ channel

Question 5

Benzodiazepines bind to ________ to facilitate GABA inhibitory action

Answer 5

GABA (A) receptor

Question 6

Tiagabine: Inhibits reuptake of _____ by transporter

Answer 6

GABA

Question 7

________ Inhibits degradation of GABA by GABA-T (GABA transaminase)

Answer 7

Vigabatrin:

Question 8

Describe the synthesis of glutamate

Answer 8

Dependent on interaction between nerve terminals and glial cells. Glutamate is formed from glutamine by the action of glutaminase in the nerve ending.

Newly synthesized glutamate is stored in synaptic vesicles for subsequent release.

Question 9

Released glutamate either reenters the neuron via a neuronal glutamate transporter [Gt (n)] or is taken up by the glial cell transporter [Gt (g)] and is converted to glutamine by __________ in the glial cell

Answer 9

glutamine synthetase

Question 10

Glutamate has a Pathophysiological Role in:

Answer 10

• Epilepsy
• Ischemic brain damage
• Addiction
• Schizophrenia

Question 11

Acetylcholine (ACh) Synthesis is Catalyzed by ______

Answer 11

choline acetyl transferase

Question 12

ACh is taken up into storage vesicles and packaged for release by the action of the _______

Answer 12

vesicle-associated transporter (VAT)

Question 13

Muscarinic receptors

M1-M3 Do what when activated?

Answer 13

activate Gq -> stimulate PLC activity

Question 14

M2-M4 receptors when activated do what?

Answer 14

activate Gi/o -> inhibit adenylyl cyclase activity

Question 15

Nicotinic receptors: NN when activated do what?

Answer 15

open receptor-gated cation channel [ionotropic]

Question 16

The Rate-limiting enzyme for both DA and NE synthesis is ________

Answer 16

tyrosine hydroxylase (TH)

Question 17

The Rate-limiting enzyme for 5HT (seretonin) synthesis is _______

Answer 17

tryptophan hydroxylase (TpH)