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Titolo:
MUSCLE LENGTH ALTERS GEOMETRY OF ARTERIOLES AND VENULES IN HAMSTER RETRACTOR
Autore:
NAKAO M; SEGAL SS;
Indirizzi:
YALE UNIV,SCH MED,JOHN B PIERCE FDN LAB,290 CONGRESS AVE NEW HAVEN CT06519 YALE UNIV,SCH MED,JOHN B PIERCE FDN LAB NEW HAVEN CT 06519 PENN STATE UNIV,NOLL PHYSIOL RES CTR UNIVERSITY PK PA 16802
Titolo Testata:
American journal of physiology. Heart and circulatory physiology
fascicolo: 1, volume: 37, anno: 1995,
pagine: 336 - 344
SICI:
0363-6135(1995)37:1<336:MLAGOA>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
HEAVY RHYTHMIC EXERCISE; BLOOD-FLOW; SKELETAL-MUSCLE; SUSTAINED CONTRACTION; CALF MUSCLE; RAT; CAPILLARY; DIAPHRAGM; PRESSURE; MICROVESSELS;
Keywords:
MICROCIRCULATION; MUSCLE BLOOD FLOW; NETWORK TOPOLOGY; MUSCLE MECHANICS; SARCOMERE LENGTH;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
30
Recensione:
Indirizzi per estratti:
Citazione:
M. Nakao e S.S. Segal, "MUSCLE LENGTH ALTERS GEOMETRY OF ARTERIOLES AND VENULES IN HAMSTER RETRACTOR", American journal of physiology. Heart and circulatory physiology, 37(1), 1995, pp. 336-344

Abstract

We investigated how changes in muscle length (L(m)) would alter the geometry of arterioles and venules and whether such an effect would depend on the orientation of microvessels to muscle fibers. The parallel-fibered retractor muscle of anesthetized (pentobarbital sodium, 65 mg/kg) male hamsters (n = 20, 105 +/- 4 g) was exposed and irrigated withphysiological saline solution (pH 7.4; 35 degrees C). Sarcomere length (L(m)) was measured at x2,400 magnification after topical application (3 min, 10(-5) M) of a fluorescent dye [4-(4-diethylaminostyryl)-N-methylpyridinium iodide]. In vivo L(m) at resting L(m) (i.e., at L(m) =100%) was 3.00 +/- 0.02 mu m. The origin and insertion of the retractor were cut, and the muscle was reflected dorsally while the circulation arising from the ventral surface was preserved. Polystyrene ''tendons'' were glued to each end of the muscle to control L(m), which was varied in 10% increments from 80 to 130% of in situ L(m); L, increased linearly (r(2) = 0.82) from 2.58 +/- 0.03 to 3.89 +/- 0.07 mu m, respectively. Arteriole and venule branches and the centerline of ''Y'' bifurcations were classified based on orientation angles (theta) with respect to muscle fibers at L(m) = 100%; three categories were defined using trigonometry (detailed in the APPENDIX) based on microvessel behavior during changes in L(m): parallel (P), O degrees less than or equalto theta less than or equal to 32.6 degrees; intermediate (I), 32.6 degrees < theta < 59.4 degrees; and normal (N), 59.4 degrees less than or equal to theta less than or equal to 90 degrees. Similar effects (P< 0.05) of L(m) were observed for arterioles and venules; therefore, results were pooled. As L(m) increased from 80 to 130%, the distance between branch points decreased for N and increased for P vessels, bifurcation angle increased for N and decreased for P vessels, and diameter increased for N vessels while vessel curvature decreased for P and increased for N vessels. We conclude that L(m) exerts a pronounced effect on the geometry of arterioles and venules that varies with the orientation of microvessels to muscle fibers.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 13/07/20 alle ore 20:09:07