Vasopressin has three main effects: 1  Increasing the water permeability of distal convoluted tubule and collecting duct cells in the kidney, thus allowing water reabsorption and excretion of more concentrated urine, i.e., antidiuresis.
It can be caused by damage to the vagus nerve, which regulates the digestive system. A damaged vagus nerve prevents the muscles in the stomach and intestine from functioning, preventing food from moving through the digestive system properly. Often, the cause of gastroparesis is unknown.
Some Common Causes. Sometimes a muscle spasm in the stomach will occur when one is constipated. Once the constipation has been successfully dealt with, the spasms will cease. Pressure is one of the possible causes of a stomach spasm or cramp. Remove the pressure, or the source of the pressure, and the stomach muscles will stop misbehaving. Dehydration is another common cause.