Channelopathy

Question 1

Na Channel Structure:

Answer 1

voltage gated sodium channel has ɑ and auxiliary subunits

ɑ subunit: 4 domains (I-IV) each with 6 transmembrane regions; each domain (of 6) has aqueous pore between them

Question 2

Na Channel Disease: cause

Answer 2

point mutation in AA

Question 3

Na Channel Disease: Generalized Epilepsy with Febrile Sickness (GEFS):

Answer 3

↓inactivation of Na channels —> ↑excitability

Question 4

Na Channel Disease: Myotonia / Paralysis:

Answer 4

Na mutation in skeletal Na muscle (the other excitable cells other than neurons)

Question 5

Ca Channel Structure:

Answer 5

voltage gated Ca channel with ɑ subunits ~ Na channel (4 domains of 6 transmembrane proteins each)

Question 6

Familial Hemiplegic Migraine:

Answer 6

mutation in P/Q Ca channel (Cav2.2)

Question 7

Episodic Ataxia Type 2:

Answer 7

truncated Cav2.2

Question 8

Congenital Stationary Night Blindness:

Answer 8

truncated L-type Ca channels —> Δsensitivity of channels to calmodulin effects

Question 9

Lambert Eaton Syndrome:

Answer 9

auto-Abs to pre-synaptic Ca channels —> no SNARE/vesicle interaction —> no AcH

Question 10

K/Cl Channels Diseases: Myotonia

Answer 10

(↑excitability of muscles): mutation in Cl- channel (in muscle Cl- determines resting potential; mutation = more +)

Question 11

K/Cl Channels Diseases: Episodic Ataxia Type 1:

Answer 11

mutated K channels in Purkinje Cells (Kv1.1)

Question 12

K/Cl Channels Diseases: Benign Familial Neonatal Seizures:

Answer 12

mutation in KCNQ2 coding voltage gated K+ channel