Unbound receptors are internalized at a relatively slow rate, on average once every 30 minutes, and are recycled rapidly to the plasma membrane so there is little reduction in the total number of surface receptors. 

TLS Online TPP Program

#Id: 9091

#XL - T Zoology

The resultant efflux of NaCl triggers massive water loss through the intestine as cells respond to the ensuing osmotic imbalance causes severe dehydration and electrolyte loss.

TLS Online TPP Program

#Id: 9092

#XL - T Zoology

Pertussis toxin, produced by Bordetella pertussis, catalyzes ADP-ribosylation of the  subunit of Gαi, preventing GDP-GTP exchange and blocking inhibition of adenylyl cyclase.

TLS Online TPP Program

#Id: 9093

#XL - T Zoology

Ligand binding to GPCRs that activate Gαq, leading to activation of phospholipase C

TLS Online TPP Program

#Id: 9094

#XL - T Zoology

Phospholipase C cleaves a phospholipid known as PI(4,5) P2, generating two second messengers: 

diffusible IP3 and membrane-bound DAG

TLS Online TPP Program

#Id: 9095

#XL - T Zoology

TLS Online TPP Program

#Id: 9096

#XL - T Zoology

IP3 triggers the opening of IP3-gated Ca²+ channels in the ER and elevation of cytosolic free Ca²+.