1. Long-term administration of the
adenosine receptor antagonist,
1,3-dipropyl-8-sulfophenylxanthine (
DPSPX), causes arterial
hypertension and cardiovascular hypertrophic and hyperplastic changes (Matias, Albino-Teixeira, Polónia & Azevedo, 1991). As
somatostatin is a repressor of cell growth, and
adenosine is a potent inducer of the
somatostatin gene, we investigated the putative involvement of
somatostatin in the cardiovascular effects of
DPSPX. 2.
DPSPX (90 micrograms kg-1 h-1, i.p.) or saline and the
somatostatin analogue,
octreotide (75 micrograms kg-1 day-1, s.c.), or saline were infused through Alzet minipumps to Wistar rats. Blood pressure was measured with the tail-cuff technique. Seven days after implantation of the minipumps the rats were killed and the tissues prepared for microscopy. 3.
DPSPX induced arterial
hypertension and cardiovascular hypertrophic and hyperplastic changes as previously described (Matias et al., 1991). Treatment of the rats with
octreotide alone had no effect either on blood pressure or in blood vessel morphology. However,
octreotide prevented both the hypertensive and the cardiovascular morphologic effects of
DPSPX. 4. The results are compatible with the involvement of
somatostatin in the long-term cardiovascular effects of
adenosine.