Norepinephrine uptake and efflux from canine peripheral collateral arteries

Area of Science:

• Vascular biology
• Neuropharmacology
• Physiology

Background:

• Collateral arteries exhibit altered norepinephrine (NE) content and release compared to normal arteries.
• The underlying mechanisms of impaired neuronal function in collateral arteries remain unclear.

Purpose of the Study:

• To investigate basal neuronal function in developing collateral arteries.
• To determine if limitations in NE reuptake or release contribute to NE depletion in collateral arteries.

Main Methods:

• Assessed NE uptake via [14C]l-NE accumulation in collateral and branch arteries.
• Examined the effects of cocaine and normetanephrine on NE uptake.
• Measured NE efflux using [14C]l-NE and endogenous NE, with and without cocaine, corticosterone, and pargyline.

Main Results:

• NE uptake was significantly lower in collateral arteries compared to branch arteries.
• Cocaine and normetanephrine impaired NE uptake in branch arteries but not collateral arteries.
• NE efflux was greater from collateral arteries, and cocaine differentially affected endogenous NE efflux in collateral versus branch arteries.

Conclusions:

• Decreased NE in collateral artery sympathetic neurons results from both reduced NE uptake and increased NE efflux.
• These findings elucidate the neurochemical basis for altered sympathetic function in developing collateral arteries.