G-Protein systems

Shortcut Pathway

from receptor to G-protein to ion channel-fast and localized

second messenger cascade pathway

process that couples the neurotransmitter via multiple steps to activation of a downstream enzyme

G-protein

couples neurotransmitters with downstream enzyme activation

Gi

adenylyl cyclase inhibitory Ga protein

Gs

adenylyl cyclase stimulatory Ga protein

Divergence

one transmitter activates more than one receptor subtype and has greater postsynaptic response

Convergence

different transmitters converge to affect same effector system

Integrative Divergence and Convergence

Describes how multiple signals can either activate various pathways (divergence) or how different signals can influence a single pathway (convergence) in G-protein signaling.