Stimulatory Effects of Neuronally Released Norepinephrine on Renin Release from Rat Kidney Cortical Slices

ABSTRACT

Stimulatory effects of extracellular high K⁺ in the presence of nifedipine (NIF) on renin release (RR) from kidney cortical slices were investigated. The stimulation was suppressed either by propranolol or by metoprolol but not by prazosin. High K⁺ plus NIF-induced increase in RR was attenuated by renal denervation. The enhancing effect was not observed when the slices were incubated in Ca²⁺ -free buffer or in medium containing divalent cations such as Cd²⁺, Co²⁺ and Mn²⁺. These alterations in RR correlated with ³H-efflux from the slices preloaded with ³H-norepinephrine. We conclude that the high K⁺ plus NIF-induced increase in RR from the slices is mediated by norepinephrine (NE) derived from renal sympathetic nerves and that this neuronally released NE stimulates RR via the activation of β-adrenoceptors.

Key words::

• Renin secretion
• Sympathetic nerve ending
• High potassium depolarization
• ³H-Norepinephrine
• Voltage-dependent calcium channel
• β-Adrenoceptors