The effects of combined angiotensin converting enzyme inhibition and β‐adrenoceptor blockade on plasma renin activity in anaesthetized dogs

Abstract

1 The effects of P-adrenoceptor blockade on the changes in plasma renin activity (PRA) following angiotensin enzyme (ACE) inhibition were investigated in pentobarbitone-chloralose anaesthetized dogs. 2 ACE-inhibition, with enalapril (2 mg kg-'), caused a significant reduction in systemic arterial blood pressure (BP) with little or no effect on cardiac function, and a significant elevation of plasma renin activity (PRA). By contrast P-adrenoceptor blockade with atenolol (1 mg kg-'), caused a similar reduction in BP but in addition, significantly reduced cardiac function and PRA. 3 A combination of enalapril with atenolol, caused a significant reduction in BP, cardiac function and PRA, hence there was no elevation of PRA, as was seen following ACE-inhibition with enalapril alone. 4 The observations with P-adrenoceptor blockade alone, show that there is an important homeostatic role for the renal sympathetic innervation, mediated by P-adrenoceptors, in controlling basal renin levels. Furthermore, the renal sympathetic innervation appears to be an important contributor to the renin release caused by an ACE-inhibitor as the additional presence of a P-adrenoceptor blocking agent will prevent this release.5 BW B385C (2 mg kg-'), which combines both ACE-inhibition and P-adrenoceptor blocking properties, also produced reductions in BP and cardiac function similar to those seen with the enalapril/ atenolol combination. In addition, for an equivalent degree of ACE-inhibition by BW 385C, to that seen with enalapril alone, the elevation of PRA was attenuated.6 A combination of ACE-inhibition and P-adrenoceptor blocking activity in a single entity, such as BW B385C, therefore also produces a reduced renin release when compared with an ACE-inhibitor, such as enalapril. This provides further confirmation of the importance of the renal sympathetic innervation in the renin response to ACE-inhibition, and supports the concept of combining ACEinhibition with P-adrenoceptor blockade.

Effect of meloxicam or robenacoxib administration timing on renal function and postoperative analgesia in cats undergoing ovariohysterectomy: A randomized, blinded, controlled clinical trial

“…The renin‐angiotensin system must therefore have been activated during anaesthesia independently of cyclo‐oxygenase inhibition, possibly due to hypotension or surgical stimulation. This has been shown in dogs and humans, in which beta‐adrenoceptor blockade causes a suppression of plasma renin, indicating that renal sympathetic innervation is also involved in this response (Cambridge et al., 1992). PRA was higher at 2 h after the end of the surgery in admission groups compared with induction groups.…”

Biomedical Significance of Tryptamine: A Review

“…Similarly in mammalian CNS, tryptamine and its derivatives such as dimethyltryptamine so-called "trace amines" act as neuromodulator [27]. Neuropsychiatric manifestations arises due to the disturbance in synthesis and metabolism of tryptamine and urinary output of tryptamine is correlated with increasing severity of psychosis as Schizophrenic, Parkinsonion and depressed patients has disturbed urinary output of tryptamine [28].…”