Figure 1. Dehydration increases the firing rate of continuously active and phasic, but not irregular, vasopressin cells.

A, ratemeter records (in 1 s bins) of the firing rates of supraoptic nucleus vasopressin neurones in euhydrated rats (left) and 24 h dehydrated rats (right), displaying spontaneous continuous activity (top), phasic activity (middle) and irregular activity (bottom). B, the mean firing rates (±s.e.m.) of continuous (top), phasic (middle) and irregular (bottom) vasopressin neurones in euhydrated rats and dehydrated rats (*P < 0.05, unpaired t test).