Random things I picked up and didn't want to add to other decks

Question 1

what role does Cl- play in the excitability of a neuron?

Answer 1

The increaseing Cl- current make it more difficult to reach the threshold for and AP as the cell becomes more depolarized. They are a hyperpolarizing current

Therefore, if we increase or prolong the action of the Cl- channels the cell is less excitable

Question 2

what medications target the Cl- channel at the GABA_A receptor?

Answer 2

Benzodiazpines (pams, and lams) work by increasing the opening frequency of the channel

barbituates increase the duration that the channel is open

topirimate inceases the frequency that the channels open but it is through a different mechanism than the benzos

Question 3

what receptors mediate the effect of glutamate in the post synaptic cell?

Answer 3

NMDA

AMPA

metabotropic

Question 4

GABA_A is related to________ channels

GABA_B is related to ______ channels

Answer 4

GABA_A is related to Ca++ channels

GABA_B is related to K+channels

Question 5

what are the mechanisms that lead to increased excitation of a neuron

Answer 5

The mechanisms that lead to increased excitation of a neuron are:

increased activation of NMDA receptors

increased syncronity between neurons

increased activation due to recurrent excitatory channels

Question 6

What is the key calcium channel in the thalamic reticular nurons that may play a role in generalized seizure activity?

Answer 6

The transient, low threshold T2-calcium channels in the thalamus are key to the oscillations in the resting membrane potential of the neurons. They become available when the cell is hyperpolarized and open transiently with depolarization.

They are activated through GABAB receptors.

they make “the burst” mode possible

They are open when inactive and closed when they are active.

Question 7

What role do the T-channels play in absence seizures?

What effect does giving a GABA_B receptor agonist have on patients with Absence seizures?

Answer 7

In an absence seizure, there is an abnormal activation of the cortex that is usually active during non-REM sleep due to an altered GABA_B inhibition. This abnormal inhibition could be caused by the T-type calcium channels but it is still unclear.

Giving a GABA_B agonist to someone with absence seizures results in an exacerbation of the seizures.

Question 8

What anticonvulsants suppress the T-type calcium channel?

what type of seizure are they used for?

Answer 8

Some anti convulsants that prevent absence seizures by supressing the T-type calcium channel current are

Valproic Acid

ethosuximide

**you can also give lamotrigine for asence and myoclonic seizures in children. It supresses the rapid firing of neurons and inactivates Na+ channels and inhibits the voltage-gated calcium channel so its harder to reach the threshold for an AP

Question 9

What anticonvulsants increase GABA levels?

Answer 9

Tiagabine and vigabatrin increase GABA levels. The increased GABA levels increase the syncronisity of the thalamocortico circuit and increase the number of T-type channels that are available which will exacerbate absence seizures.

Question 10

What type of seizure is common in children and early adulthood?

What causes of seizure are strongly coorelated with

1. early childhood
2. early adulthood
3. middle adulthood
4. older adults

Answer 10

Absence seizures are common in children and early adulthood. Children normally grow out of them

What causes of seizure are strongly coorelated with

1. early childhood: birth injury, febrile, infection, metabolic (metabolic associated seizures are also seen in early adulthood- onset in the 20s)
2. early adulthood- trauma, idiopathic
3. middle adulthood- tumor
4. older adults-stroke