Angiotensin tachyphylaxis

Paiva et al. (1988) studied the role of sodium ions in angiotensin tachyphylaxis in the guinea-pig ileum and taenia coli. 

As tachyphylaxis due to angiotensin can be prevented when the time between injections is sufficiently long in duration (14) or when the dissociation of the complex receptor - peptide is acdele-rated (20), it may be concluded that tachyphylaxis is due to resi-dually bound peptide. We therefore prefer the term auto-inhibition as the reduction of response is due to angiotensin itself and not to a persistent modification of muscular tissue. It must be noted that angiotensin tachyphylaxis on guinea-pig ileum is partially specific in that angiotensin renders the smooth muscle insensitive to itself but furthermore reduces its sensitivity to brady-kinin and in a lower extent to histamine in these conditions, action of acetylcholine is potentiated. 

Angiotensin II receptors [152], endothelin receptors [153] and vasopressin Via receptor (VlaR) and V2 receptor (V2R) receptors [154] have been isolated in rat arterioles. In isolated rabbit arterioles, the vasoconstrictor response of angiotensin II is counteracted by vasoddatory prostaglandins and nitric oxide [155]. The calcium response to angiotensin II in the isolated rabbit afferent arteriole shows tachyphylaxis [156]. This... 

The response to angiotensin is influenced by previous administration of the peptide. It may be decreased (tachyphylaxis) or potentiated. The analysis of the conditions under which potentiation or inhibition occurs has shown that the rate of dissociation of the angiotensin-receptor complex is the determining factor (Godfraind). 

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