Gi/o-coupled serotonin receptor activity

Combining with serotonin and transmitting the signal across the membrane by activation of the Gi/o subunit of an associated cytoplasmic heterotrimeric G protein complex. The Gi/o subunit subsequently inhibits adenylate cyclase and results in a decrease in cyclic AMP (cAMP) levels.

angiotensin type II receptor activity

An angiotensin receptor activity that acts via Gi protein coupling and cGMP (NO) generation, and may also act via additional signaling mechanisms.

dopamine neurotransmitter receptor activity, coupled via Gi/Go

Combining with the neurotransmitter dopamine and activating adenylate cyclase via coupling to Gi/Go to initiate a change in cell activity.

alpha2-adrenergic receptor activity

Combining with epinephrine or norepinephrine to initiate a change in cell activity via activation of a G protein, with pharmacological characteristics of alpha2-adrenergic receptors; the activity involves transmitting the signal to the Gi alpha subunit of a heterotrimeric G protein.

obsolete adenylate cyclase-inhibiting G protein-coupled acetylcholine receptor signaling pathway involved in negative regulation of heart rate

OBSOLETE. An adenylate cyclase-inhibiting G protein-coupled acetylcholine receptor signaling pathway that contributes to a decrease in frequency or rate of heart contraction through inhibition of adenylate cyclase (AC) activity. Binding of acetylcholine to a G protein-coupled (muscarinic) receptor on the surface of the signal-receiving cell results in the activation of an intracellular Gi/o protein. Gi/o inhibits adenylate cyclase to decrease cyclic-AMP (cAMP) levels. Since cAMP binds directly to F-channels to allow an inward flow of sodium (funny current, If current), a reduction in cAMP reduces the funny current to bring about membrane hyperpolarization and a decrease in heart rate.