Bovine lactoferrin has a nitric oxide-dependent hypotensive effect in rats

Area of Science:

• Cardiovascular Physiology
• Protein Biochemistry
• Pharmacology

Background:

• Lactoferrin (LF) is a milk protein with diverse functions.
• Its role in cardiovascular regulation, particularly blood pressure, remains largely unexplored.
• Neutrophils increase LF production during inflammation.

Purpose of the Study:

• To investigate the cardiovascular effects of bovine lactoferrin (BLF).
• To determine the impact of BLF on mean blood pressure (MBP) and heart rate (HR) in anesthetized rats.
• To elucidate the vascular mechanisms underlying BLF's hypotensive action.

Main Methods:

• Administered BLF intravenously to urethane-anesthetized rats.
• Measured MBP and HR responses to BLF and pharmacological agents.
• Assessed BLF-induced vasodilation in isolated rat thoracic aorta rings.
• Utilized inhibitors of nitric oxide synthase (l-NAME), opioid receptors (naloxone), and cyclooxygenase (diclofenac).

Main Results:

• BLF caused a dose-dependent decrease in MBP without affecting HR.
• The hypotensive effect was mediated by nitric oxide (NO) production and endothelium-dependent vasodilation.
• Central opioid pathways may also contribute to BLF-induced hypotension.
• BLF did not affect heart rate or responses mediated by muscarinic receptors or cyclooxygenase.

Conclusions:

• Bovine lactoferrin (BLF) exerts a hypotensive effect through endothelium-dependent vasodilation.
• Nitric oxide (NO) production is a key mediator of BLF's blood pressure-lowering action.
• Central opioidergic systems might also play a role in BLF's cardiovascular effects.