Lectures 4,5 amd 6 Flashcards
(131 cards)
What do the spinal nerves do?
Send information to and from the periphery
What does the dorsal tract do?
Receives sensory information from the periphery (afferent pathway)
What does the ventral tract do?
Sends information to muscles/ organs (efferent tract)
What does glutamate do?
Lead to an entry of sodium ions into the cells. If depolarisation is high enough it will stimulate an action potential
Give examples of some excitatory neurotransmitters
Glutamate and serotonin
Give some examples of inhibitory neurotransmitters
Gamma amino butyric acid (GABA) and glycine
Give some examples of some excitatory and inhibitory neurotransmitters
Acetylcholine Epinephrine (adrenaline) Norepinephrine (noradrenaline) Dopamine Endorphins
What are ionotropic receptors?
Ion channels which open upon binding of the neurotransmitter
What are metabotropic receptors?
Couples to intracellular signalling proteins (G-proteins) which then open ion channels. Depending on the repertoire of ion channels targeted by these proteins (e.g. sodium, potassium or chlorine) The is can lead to an EPSP or an IPSP
What is GABA?
The most important inhibitory neurotransmitter in the CNS
What are GABA A receptors? How do they work?
Chloride channels. Binding of GABA to the receptor opens the channel, leading to an entry of chloride ions. This hyperpolarises the postsynaptic membrane, leading to an IPSP
What does low GABA levels lead to?
Restlessness, anxiety and irritability
What does pharmacological enhancement of GABA receptors lead to?
Reduces anxiety and mild tranquilisation
What is glutamate?
The most abundant excitatory neurotransmitter in the vertebrate CNS
What are the three subtypes if iontropic glutamate receptors?
AMPA, Kainate and NMDA
What is the subtype of ionotropic glutamate receptors, NDMA receptors unusual?
It is blocked by Mg2+ - thereby preventing ions to pass through the channel even if glutamate is bound.
When the membrane depolarises what happens to NDMA receptors?
Mg2+ is electrostatically forced out of the channel and allows ions (Na2+ and Ca2+) to pass through
What is long term potentiation important in?
Memory and learning
What is the alternate name for serotonin?
5-HT (5-hydroxy tryptamine)
What does serotonin regulate?
Emotions, body temperature, sleep cycle and the digestive system
What are serotonin imbalances involved in?
Depression, impulsive behaviour or sleep disorders
There is a large variety of serotonin receptors. what are most of them?
Metabotropic
What are nicotine can acetylcholine receptors?
They are sodium channels. They are the major receptors in skeletal muscle cells and in the autonomous nervous system
What are nicotinic acetyl choline receptors (nAChR) activated and inhibited by?
Activated by nicotine and inhibited by alkaloid arrow poisons (Curare)