Bioassay of vasopressin on the rabbit isolated urinary bladder

Abstract

The rabbit isolated urinary bladder contracted in the presence of Lys8-vasopressin from threshold concentrations of 5 to 30 μ ml−1 (0·02 to 0·11 ng ml−1). Responses were proportional to the dose used. The tissue gave satisfactory results either fresh or after storage for several days in cold Tyrode or Krebs solution (3–4°). The preparation also contracted in the presence of oxytocin, but it was 7 to 20 times less sensitive to this peptide. A number of other peptides and amines known to stimulate smooth muscle showed low activity on the rabbit urinary bladder and, occasionally, intense tachyphylaxis.