Bio 1-L10-Signalling via Ligand Gated Ion Channels

what causes action potential depolarisation?

1. ligand gated na channels

2. voltage gated na channels

neurons general info:

• cannot depolarise without ligand gated sodium channels that open these

• need VOLTAGE channels for sodium

glutamate neuron example

• responds by sodium channels opening- ligand gate

• passes electrical stimulus- turns into chemical signal

• when bound- turns electrical again

GABA inhibitory neurotransmitter example

• allow chlide in- hyperpolarises

• makes it harder to action

steps in these channels for neurons:

1. dendrites- ligand gated Na channels- causes depolarisation

2. opens voltage gated Na channels- causes action potential

3. voltage gated Na channels for action potential which triggers voltage gated potassium channels- no back propogation

types of neurotransmitter receptors

1. ionotropic- ligand gated ion channels

2. metabotropic- indirect gating of ion fluxdue to signalling changes- ion G proteins and tyrosine kinase

2 receptor classes

1. nicotinic- ionotropic

2. muscarinic- metabotropic

nicotinic receptors- example

• acetylcholine receptors

• pentamer- 4 alpha helices

• when it binds it changes confirmation of protein- m2 twists and allows ions in