Transmural pressure during cardiogenic oscillations in rodent diaphragmatic lymphatic vessels.
BACKGROUND
The mechanism of initial lymphatic filling and the role of cardiogenic tissue motion in promoting lymph formation and propulsion are at present still controversial issues, in particular when considering interstitial tissues whose fluid pressure is well below atmospheric. To elucidate these aspects, the micropuncture technique was used to record interstitial (P(int)) and intralymphatic pressure (P(lymph)) simultaneously in the diaphragmatic lymphatic plexus draining the pleural cavity.


RESULTS
The diaphragmatic lymphatic network was identified in anesthetized rabbits and rats through fluorescent dextrans injected intrapleurally. All P(lymph) and P(int) traces were pulsatile, oscillating either in-phase (33% of traces) or out-of-phase (67%) during cardiogenic swings. P(lymph) swept between -4.1 +/- 0.9 (SE) mmHg and 3.5 +/- 1.1 mmHg in rabbits, and between -5.1 +/- 1.0 mmHg and -2.7 +/- 1.1 mmHg in rats. P(int) oscillated between -0.8 +/- 0.7 mmHg and 4.9 +/- 0.7 mmHg in rabbits, and between -0.6 +/- 0.8 mmHg and 0.9 +/- 0.7 mmHg in rats.


CONCLUSIONS
The data revealed a great functional complexity of the diaphragmatic lymphatic network and suggested that cardiogenic oscillations may play an important role in promoting lymph formation and propulsion from interstitial tissues with subatmospheric tissue pressure.
Negrini
Daniela
D
Dipartimento di Scienze Biomediche Sperimentali e Cliniche, Università degli Studi dell'Insubria, Varese, Italy. Daniela.Negrini@uninsubria.it
Moriondo
Andrea
A
Mukenge
Sylvain
S
D000818:Animals; D003911:Dextrans; D003964:Diaphragm / Q000502:physiology*; D005260:Female; D005456:Fluorescent Dyes; D006321:Heart / Q000502:physiology*; D042601:Lymphatic Vessels / Q000502:physiology*; D008297:Male; D011817:Rabbits; D051381:Rats
D003911:Dextrans; D005456:Fluorescent Dyes