[1-Sarcosine]-angiotensin II tachyphylaxis in helical strips and everted rings of rabbit aorta

The development of tachyphylaxis to [1-sarcosine]-angiotensin II was studied in helical strips and everted rings of rabbit aorta. Strips, but not everted rings, developed marked (greater than 50%) tachyphylaxis to the peptide, when challenged repeatedly at 1-h intervals. Measurements of the membrane potentials showed no difference between the two preparations, but strips were more sensitive to KCl than everted rings. These results suggest that the strips are more depolarized than the everted rings due to lesions caused by the spiral cutting. This partial depolarization may underlie the tachyphylactic phenomenon.