Excitable tissue Flashcards
Ligands for NMDA receptor
Glutamate
Aspartate
NMDA receptor functions
Pain transmission
Memory
What blocks NMDA ?
Ketamine pcp
Conduction velocity of action potentials influced by ?
Cell diamter: the bigger the fast
Mylenation : faster
Demylinating diseases
Multiple sclerosis = CNS
Causes hyperflexia
Guillain barre = peripheral
Causes hypoflexia
Na unable to reach to threahhold cause of loss of myline causes leaking of current = conduction block
What is the primary mechanism stopping synaptic transmission of nor-adenregic neurons?
Reuptake
The 3 state of na fast channel
1- closed
2- open
3- inactivated
Go back to closed
When is inactivated phase occurs ?
When the membrane potential is postive
Causing h gates to close
What happens to Na gates in hyperkalemia ?
Na fast voltage gates , get stuck in inactivated state , prevents m gates to close , hence decrease the number of fast na channel to open again
Leading to less excitability
What drug blocks fast Na channels to ?
Tetrodotoxin (TTX)
Saxitoxin(STX)
Caine drugs
Therapy to prevent an action potentials
Toxins that block the inactivation of fast Na channels
Ciguatoxin (ctx)
Batrachotoxin (BTX)
Action can happen in _____ period
But cant happen in ____ period
1- relative refactory :due to elevated k
2- absolute period : due to fast Na channels being at open or inactived state
What breaks ach ?
Ache
Excitory receptors
Inhibitory receptors
Excitory :
Nicotintic - nonNMDA - NMDA
Inhibitory : GABA - Glycine
Toxin destory protein needed for fusion and release of synaptic veaicle …. results in flaccid paralysis
Botulinum toxin ( botox )
