Neuronal and endothelial nitric oxide synthase gene knockout mice

Area of Science:

• Physiology
• Neuroscience
• Cardiovascular Science

Background:

• Nitric oxide (NO) plays critical roles in various physiological processes.
• Neuronal nitric oxide synthase (nNOS) and endothelial nitric oxide synthase (eNOS) are key isoforms of NO production.
• Understanding the specific functions of nNOS and eNOS is crucial for comprehending NO's broader impact.

Purpose of the Study:

• To investigate the distinct physiological roles of nNOS and eNOS using genetically modified knockout mice.
• To elucidate the involvement of nNOS and eNOS in gastrointestinal motility, cerebral ischemia, neurotransmitter release, vascular response to injury, and cardiac function.

Main Methods:

• Generation and analysis of nNOS and eNOS knockout mice.
• Assessment of gastrointestinal motility, infarct size in focal ischemia models, neurotransmitter release, neointimal proliferation after vascular injury, and cardiac contractile responses.

Main Results:

• nNOS knockout mice exhibit enlarged stomachs and impaired gastrointestinal motility, and smaller infarcts in cerebral ischemia models.
• eNOS knockout mice display hypertension, lack endothelium-derived relaxing factor activity, develop larger infarcts, and show increased neointimal proliferation.
• eNOS knockout mice demonstrate altered cardiac function, with preserved gender-specific protection and modulation by atrial natriuretic peptide.

Conclusions:

• nNOS and eNOS isoforms have distinct and critical roles in regulating physiological functions.
• nNOS is implicated in neurotoxicity in cerebral ischemia, while eNOS is vital for maintaining vascular homeostasis and normal cardiac function.
• These knockout models provide valuable insights into the specific contributions of each NO synthase isoform to health and disease.