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ACL deficiency impairs the vasoconstrictive efficacy of neuropeptide Y and phenylephrine in articular tissues: a laser speckle perfusion imaging study
- Source :
- Journal of applied physiology (Bethesda, Md. : 1985). 98(1)
- Publication Year :
- 2004
-
Abstract
- Sympathetic-derived neuropeptide Y (NPY) helps regulate inflammatory responses in injury and disease, is a vasoconstrictor, and stimulates angiogenesis. Rupture of the anterior cruciate ligament (ACL) is a common clinical presentation that results in tissue inflammation, hyperemia, and angiogenesis in the intact medial collateral ligament (MCL). This study is the first to examine the vasoregulatory role of NPY in ACL-deficient knee joints by using the newly developed technique of laser speckle perfusion imaging (LSPI). MCL blood flow was measured in two groups of adult rabbits: unoperated control ( n = 6), and 6-wk ACL transected ( n = 5). Under anesthesia, the MCL was surgically exposed and tissue blood flow was imaged at high resolution using LSPI. NPY was applied to the MCL vasculature in topical boluses of 100 μl (dose range 10−14 to 10−9 mol), and the α-adrenoceptor agonist phenylephrine was applied in doses of 10−14, 10−10, and 10−7 mol. In control rabbits, topical administration of NPY or phenylephrine produced dose-dependent vasopressor responses (maximal effect at 10−9 mol NPY and 10−7 mol phenylephrine). In ACL-transected knees, there was little or no vasoconstrictive response to NPY at any dose. The response to phenylephrine was significantly reduced compared with control ligaments. Possible causes of the reduced vasoconstrictive response to NPY in the MCL after 6 wk of ACL deficiency include development of tolerance to the peptide due to a prolonged increase in sympathetic nerve activity or change in the distribution or functionality of the NPY Y1 receptors. Chronic ACL deficiency leads to profound and protracted hyperemia in associated articular tissues. Abrogation of a vasoconstrictor response to both NPY and phenylephrine in the MCL indicates that ACL deficiency induces major changes in the vascular physiological homeostasis.
- Subjects :
- Cartilage, Articular
medicine.medical_specialty
Physiology
Angiogenesis
Anterior cruciate ligament
Perfusion scanning
Osteoarthritis
Physiology (medical)
Internal medicine
Image Interpretation, Computer-Assisted
Laser-Doppler Flowmetry
Medicine
Animals
Neuropeptide Y
Anterior Cruciate Ligament
Phenylephrine
Dose-Response Relationship, Drug
business.industry
Anterior Cruciate Ligament Injuries
musculoskeletal system
medicine.disease
Neuropeptide Y receptor
Endocrinology
medicine.anatomical_structure
Vasoconstriction
Anesthesia
Ligament
Rabbits
medicine.symptom
business
Blood Flow Velocity
medicine.drug
Subjects
Details
- ISSN :
- 87507587
- Volume :
- 98
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Journal of applied physiology (Bethesda, Md. : 1985)
- Accession number :
- edsair.doi.dedup.....0f65ebb73bcedf4b0a3a2a42d4bbdcad