| Ca2+ -
a versatile signal |
| Target Tissue |
| Signaling Molecule |
| Major Responses |
| Liver |
| Vasopressin |
| Glycogen breakdown |
| Pancreas |
| ACh |
| Amylase secretion |
| Smooth muscle |
| ACh |
| Contraction |
| Mast cells |
| Antigen |
| Histamine secretion |
| Blood platelets |
| Thrombin |
| aggregation |