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Pump function in isolated juvenile rodent lymphatics (666.2)
Author(s) -
Moor Andrea,
Breslin Jerome
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.666.2
Subject(s) - lymphatic system , lymphatic vessel , contraction (grammar) , constriction , anatomy , medicine , chemistry , pathology , cancer , metastasis
Primary lymphedema typically afflicts children, however, studies of lymphatic physiology generally examine lymphatic vessels from adult animals. The goal of this study was to evaluate responses of isolated lymphatic vessels obtained from juvenile (5‐7 week old) Sprague‐Dawley rats to 1) changes in luminal pressure, or 2) substance P, an endogenous lymphatic constricting agent. Isolated lymphatics were mounted onto resistance‐matched glass micropipettes bathed in 37°C albumin physiological salt solution (APSS) at 2 cm H 2 O luminal pressure. Pressure was stepped to 4, 6, and 8 cm H 2 O. In other experiments, the response to 10 nM substance P was assessed. Video recordings were used to obtain contraction frequency (CF), end diastolic diameter (EDD), end systolic diameter (ESD), and contraction amplitude (AMP = EDD ‐ ESD). Ca 2+ ‐free APSS was used to obtain the maximal passive diameter (MaxD), and the ability of lymphatics to reestablish tone and pumping upon switching back to normal APSS was also evaluated. Tone was calculated as 100*(MaxD‐EDD)/MaxD. In response to elevations in luminal pressure, juvenile lymphatics displayed increases in EDD, ESD, and CF. In contrast, the amplitude of the phasic contractions decreased. Lymphatic tone was also diminished. After measuring passive diameter in Ca 2+ ‐free solution, upon changing back to Ca 2+ ‐containing APSS lymphatics reestablished tone and pumping respectively. The addition of substance P to the bath elicited an immediate constriction of lymphatics and increased CF over a 5 min period. Substance P also caused constriction even in the presence of 10 ‐8 ‐10 ‐7 M nifedipine, an L‐type calcium channel blocker, however lymphatic pumping did not resume. These experiments demonstrate similarities in isolated juvenile rat lymphatics with previous studies using lymphatic vessels isolated from adult rats.