Lecture 21: Cell Signaling III Flashcards
What are the steps of Receptor Gunnel Cyclases
These receptors function as enzymes and convert GTP to cGMP
*No activated gaunylyl cyclades, contain heme also convert GTP to cGMP
What are the steps of acetylcholine induced vasdilation
- Gq alpha signaling
- Caladium activates ENOS and produces NO which diffuses from endothelium cells to SMC
- NO activates a Guanylyl cyclase, which produces cGMP and activates Protein Kinase G
- PKG phosphorulates a number of targets some of which lead to a reduction in cytoplasmic CA 2+ -> vasodilation
Treatment for Erectile Dysfunction
increase cGMP synthesis diminish after stimulus ceases because a specific phosphodiesterase. It converts cGMP to the inactive 5 GMP
Viagra casauses
cGMP levels to remain elevated once raised by an appropriate stimulus accounting for the usefulnesss of this drug in the treatment of erectile dysfunction
What are the two function of nuclear receptors
hormone receptors and transcription factors
What are the steps of Type I nuclear hormone receptors
-Bound to Hip 70 in cytosol in the absent of ligand
-Hormone binding induces a conformational change
-Most often form homodimers
-Can be inhibited by IncRNAs –> although this is not unique to Type I NHR
When are type I hormone receptors used
In the absent of the ligand
When are type II hormone receptors used
When they are bound to the DNA and Corepressorand there is an absence of the ligand
The electrogenic Na+, K+ ATPase produces a transmembrane electrical potential of -______________
60 mv (inside negative)
The action of the electrogenic pump moves __________________________
3 Na out for every 2 K pumped into the neuron
_______________ binds to a receptor on the postsynaptic neuron causing its ligand gated ion channel to open. Extracelluluar Na+ and Ca 2+ to enter through this channel depolarizing the postsynaptic cell
Acetylcholine
A stimulus to this neuron causes an action potential to move along the axon (white arrow),
away from the cell body. The opening of one voltage-gated Na+ channel allows Na+ entry,
and the resulting local depolarization causes the ______________________________
adjacent Na+ channel to open, and so on.
When the wave of depolarization reaches the axon tip, voltage-gated Ca2+ channels open,
allowing ______________________
Ca2+ entry into the presynaptic neuron.
The directionality of movement of the action potential is ensured by the____________________ that follows the opening of each voltage-gated Na+ channel.
brief refractory
period
___________ cation channel-> influx of Na, K, CA
Acetylcholine
