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Cholinergic vasoregulation in normal and adjuvant monoarthritic rat knee joints
J J McDougall1, R D Elenko, R C Bray
1McCaig Centre for Joint Injury and Arthritis Research, Department of Surgery, University of Calgary, Alberta, Canada. mcdougaj@acs.ucalgary.ca
Journal of the Autonomic Nervous System
|October 6, 1998
Summary
Cholinergic nerves regulate rat knee blood flow. Inflammation impairs this control, potentially worsening joint disease by reducing vascular nourishment. Further research into non-cholinergic mechanisms is suggested.
Area of Science:
- Neuroscience
- Physiology
- Rheumatology
Background:
- Cholinergic nerves play a role in regulating blood flow in various tissues.
- The specific role of cholinergic nerves in joint vasomotor control, especially during inflammation, is not fully understood.
Purpose of the Study:
- To investigate the role of cholinergic nerves in the vasomotor control of normal and inflamed rat knee joints.
- To determine if chronic joint inflammation affects cholinergic-mediated vasoregulation.
Main Methods:
- Joint inflammation was induced using Freund's complete adjuvant in rats.
- Blood flow was measured using laser Doppler perfusion imaging.
- Responses to topical atropine (muscarinic antagonist) and intra-articular acetylcholine were assessed.
Main Results:
- Basal joint perfusion was reduced in inflamed knees.
- Atropine reduced basal perfusion, indicating cholinergic involvement.
- Acetylcholine induced dose-dependent vasodilation in normal knees.
- This vasodilatory response was attenuated in inflamed knees but preserved in contralateral knees.
Conclusions:
- Cholinergic nerves are integral to rat knee joint vasoregulation.
- Chronic inflammation impairs cholinergic vasoregulation in the affected joint.
- This impairment may exacerbate joint disease by limiting blood supply.
- Non-cholinergic mechanisms might contribute to reduced blood flow in contralateral joints.