Lecture-10-2011-Bi-CNS150

Lecture-10-2011-Bi-CNS150 - 1 Bi CNS 150 Lecture 10 Monday...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 Bi / CNS 150 Lecture 10 Monday, October 16, 2011 The G Protein Pathway in Neuroscience: A Whirlwind Journey From Neurotransmitter to Gene Activation Henry Lester Chapter 13 (Alberts Chapter 15) kinase phosphorylated protein cAMP Ca 2+ intracellular messenger receptor t s q i G protein enzyme channel effector 2 Proof of chemical synaptic transmission, 1921. Many details of the G protein pathway were first worked out for neuronal control of the heart Vagus nerve runs from the head to the heart Spontaneous heartbeats in both hearts are stopped by stimuli to the “upstream” vagus smoked drum The diffusible substance: acetylcholine acting on muscarinic ACh receptors From previous lectures 3 cytosol vesicles containing serotonin vesicles containing dopamine N H HO NH 3 + HO HO H 2 C C H 2 NH 3 + synaptic cleft G protein-coupled (muscarinic) acetylcholine receptor G protein-coupled dopamine receptor cytosol vesicles containing acetylcholine N + (CH 3 ) 3 O O G protein-coupled serotonin receptor Some postsynaptic membranes contain G protein-coupled receptors (“metabotropic” receptors) rather than ligand-gated channels 4 Several small-molecule transmitters serve as agonists for both ligand-gated channels & GPCRs (among vertebrates) Transmitter Ligand-gated channel GPCR ACh nicotinic AChR muscarinic AChR GABA GABA A GABA B glutamate iGluR mGluR serotonin 5-HT 3 5-HT n , n = 1,2, 4-7 histamine (inverts only) H n dopamine (inverts only) D n 5 On a time scale of seconds (perhaps minutes), the language of the nervous system is still electricity; and we are still describing a set of mechanisms that manipulate impulse frequencies in individual neurons. 6 GTP GDP + P i Effector: enzyme or channel outside Neurotransmitter or hormone binds to receptor α activates G protein The G protein pathway in Neuroscience How fast? 100 ms to 10 s How far? Probably less 1 μ m β γ α β γ inside 7 1. All have 7 α-helices 2. There are about 1000 G protein-coupled receptors in the genome. (Most are still “orphans”; their ligands are unknown) 3. Individual receptors respond to: (a) a low-molecular weight neurotransmitter such as serotonin, dopamine, or acetylcholine (b) a short protein (8-40 amino acids, a “peptide”) such as an endorphin (c) a relatively insoluble lipid such as anandamide, the endocannabinoid (d) an olfactory stimulus; or (e) light, in the eye (receptor = rhodopsin) G protein-coupled receptors receptor t s q i G protein cAMP Ca 2+ intracellular messenger enzyme channel effector 8 Selective advantage of such a complex pathway?...
View Full Document

This note was uploaded on 01/03/2012 for the course BI 150 taught by Professor Kennedy,m during the Fall '08 term at Caltech.

Page1 / 35

Lecture-10-2011-Bi-CNS150 - 1 Bi CNS 150 Lecture 10 Monday...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online