Question

pharmacology question

Explain briefly how an increase in systemic blood pressure would lead to a decrease in renin release?

Answer 1

Regulation of blood pressure and blood volume are through neural and homonal mechanisms.

Renin-angiotensin -aldosterone system is one of the important mechanisms for regulation of systemic blood pressure.
Renin is a hormone secreted by juxtaglomerular apparatus of kidney in response to a variety of stimuli like

• Sympathetic stimulation of JGA through β1 receptors.
• Reduced sodium entry to DCT. It is detected by macula densa.
• Reduced perfusion pressure in kidney. It is detected by baroreceptors in afferent arteriole.

When there is hypertension, Systemic blood pressure increases. Blood reaches the kidney in high pressure. This is detected by baroreceptors in the afferent arterioles. Increased perfusion pressure will lead to decrease in renin.

Here is what happens when there is an increase in BP :

when blood pressure and blood volume is high ------->increased glomerular filtration Rate( It is due to the increased glomerular hydration pressure)------->Inhibit the release of Renin from the juxtaglomerular apparatus ---->increased excretion of the water and sodium.-------->inhibition of the release of Anti diuretic hormone (ADH) from the pituitary (Negative feedback mechanism )------->Blood pressure and blood volume is lowered to Normal