Gill irrigation in Rana catesbeiana. Part II. On the musculoskeletal mechanism

1972 ◽  
Vol 50 (5) ◽  
pp. 501-521 ◽  
Author(s):  
Norman Gradwell
Keyword(s):  
Ambient Temperature ◽  
Rana Catesbeiana ◽  
Irrigation System ◽  
Muscle Fibers ◽  
Gill Cavity ◽  
Initial Depression ◽  
Bullfrog Tadpole ◽  
Narrow Opening

The jaw and hyoidean movements and the activity of certain of the muscles which cause these movements have been correlated with hydrostatic pressures in the irrigation system of the bullfrog tadpole. The jaws are capable of three modes of expression: narrow opening, wide opening, and protrusion. During inspiration the initial depression of the buccal floor is passive; active depression occurs near the end of the inspiration phase.Water flows continuously from the gill cavity and is most effusive at the onset of inspiration. Intermittent variations in the amplitude of irrigation result from natural and experimental irritation of the gill cavity. These variations, or hyperirrigations, are correlated with the activity of special muscle fibers, called fibrillic fibers, in the H1c, H2a, H3a, and B4 muscles. The respective contributions to rhythmic irrigation of the alternating buccal and pharyngeal pumps depend on ambient temperature. An auxiliary branchial force pump behind the gill clefts is powered by the H3a muscle in the soft opercular skin.

Inhibition of Zn2+-induced potentiation of twitch tension by Ni2+ in frog muscle

1986 ◽  
Vol 64 (5) ◽  
pp. 625-630
Author(s):  
Toshiharu Oba ◽  
Ken Hotta
Keyword(s):  
Action Potential ◽  
Inhibitory Action ◽  
Channel Blocker ◽  
Rana Catesbeiana ◽  
Muscle Fibers ◽  
Frog Muscle ◽  
Duration Of Action ◽  
Ringer’S Solution ◽  
Mechanical Threshold ◽  
T Tubules

Effect of Ni2+ on Zn2+-induced potentiation of twitch tension was studied electrophysiologically in the toe muscle fibers of Rana catesbeiana. The major findings of this investigation are as follows. When 2 mM Ni2+ was applied to fibers in a normal Ringer's solution containing 50 μM Zn2+ (Zn2+ solution), the Zn2+-potentiated twitch tension decreased remarkably to about one-third of that before Ni2+ treatment. This concentration of Ni2+ caused a 23% decrease in the duration of action potential which had been prolonged by Zn2+ (6.61–5.09 ms). Ni2+ (2 mM) added to normal Ringer's solution led to increases of about 30 and 42% in twitch tension and in the duration of action potential, respectively. A slight increase in the mechanical threshold was induced by 2 mM Ni2+. The inhibitory action of Ni2+ on the twitch tension in Zn2+ solution was larger than that in the case of tetanus tension. Diltiazem (40 μM), aCa2+ channel blocker, did not inhibit the twitch tension potentiated in Zn2+ solution. These results suggest that the decrease in Zn2+-potentiated twitch tension by Ni2+ may possibly derive from impairment of the propagation of action potential along the T tubules.

The respiratory importance of vascularization of the tadpole operculum in Rana catesbeiana Shaw

1969 ◽  
Vol 47 (6) ◽  
pp. 1239-1243 ◽  
Author(s):  
Norman Gradwell
Keyword(s):  
Surface Area ◽  
Respiratory Function ◽  
Rana Catesbeiana ◽  
Bullfrog Tadpole ◽  
Anuran Tadpole ◽  
First Time ◽  
Arteries And Veins

Capillary densities in the opercular membrane of the bullfrog tadpole are consistent with the postulate that this membrane has the respiratory function of increasing the surface area for blood ventilation. The arteries and veins of the opercular membrane are mapped and identified for the first time in an anuran tadpole.

The function of the ventral velum during gill irrigation in Rana catesbeiana

1970 ◽  
Vol 48 (6) ◽  
pp. 1179-1186 ◽  
Author(s):  
Norman Gradwell
Keyword(s):  
Direct Observation ◽  
Rana Catesbeiana ◽  
Buccal Cavity ◽  
Maximum Volume ◽  
Gill Cavity ◽  
Valvular Function

The direct observation of the ventral velum in normally breathing tadpoles confirms earlier evidence for a valvular function of this structure during inspiration. The ventral velum also acts as a hydrofoil during expiration and as a mucus-secreting surface for the entrapment of suspended food particles.As the volume of water pumped per irrigation cycle is normally less than the maximum volume of the buccal cavity, it is unnecessary for the pharynx also to become filled with inspired water during the sinking of the buccal floor. Therefore the ventral velum's cyclic occlusion of the buccal cavity from the pharynx is no handicap to normal irrigation; on the contrary, it is a prerequisite for the efficiency of the pharyngeal pump.The dorsal velum does not participate in valvular activity, but deflects the respiratory current downward and inward to the gill cavity via gill clefts 2, 3, and 4. Therefore the strong flow pumped into the pharynx by buccal compression is prevented from impinging directly on the ciliated groove behind the dorsal velum and thereby interfering with the transport of food into the esophagus.

Morphogenetic sequences during tadpole tail regeneration

1976 ◽  
Vol 54 (8) ◽  
pp. 1314-1325 ◽  
Author(s):  
Kristine H. Atkinson ◽  
Burr G. Atkinson ◽  
Peter A. Merrifield
Keyword(s):  
Epithelial Cells ◽  
Rana Catesbeiana ◽  
Neuromuscular Junctions ◽  
Muscle Fibers ◽  
Proximal Region ◽  
Chronological Order ◽  
Tail Regeneration ◽  
Nerve Axon ◽  
Early Stages ◽  
Tadpole Tail

The appearance of differentiated tissue types after amputation of Rana catesbeiana tadpole tail follows a precise chronological order. Migrating epithelial cells invest the wound within 3 days. Blastemal cells accumulate under the distal epithelium in the early stages when tissue debris is cleared away, then by day 11 notochordal outgrowth and nerve axon replacement predominate in the highly vascularized blastema.Fusion of the myoblasts to form the first detectable myotubes occurs in the proximal region of the regenerate by day 14. Myogenesis proceeds distally with myotubes present under the epithelium of the distal tip of the regenerate at day 19. After day 22 further increase in tail musculature is probably due to the growth of fibers already formed. At day 22 the new muscle fibers begin to anastomose with the healed ends of the old fibers. From 35 to 48 days the major remaining difference from control tissues is the size and extent of the regenerated muscle fibers; capillaries, axons, epidermis and dermis, and neuromuscular junctions are morphologically indistinguishable from unregenerated tissues.

Eugenol-induced contractions of saponin-skinned fibers are inhibited by heparin or by a ryanodine receptor blocker

2005 ◽  
Vol 83 (12) ◽  
pp. 1093-1100 ◽  
Author(s):  
Marco S. Lofrano-Alves ◽  
Edson L. Oliveira ◽  
Carlos E.N. Damiani ◽  
Ilana Kassouf-Silva ◽  
Rosalvo T.H. Fogaça
Keyword(s):  
Ryanodine Receptor ◽  
Rana Catesbeiana ◽  
Ryanodine Receptors ◽  
Muscle Fibers ◽  
Ruthenium Red ◽  
Muscle Contractions ◽  
Skinned Fibers ◽  
Receptor Blocker ◽  
Release Channel ◽  
Skinned Muscle

The effects of eugenol on the sarcoplasmic reticulum (SR) and contractile apparatus of chemically skinned skeletal muscle fibers of the frog Rana catesbeiana were investigated. In saponin-skinned fibers, eugenol (5 mmol/L) induced muscle contractions, probably by releasing Ca2+ from the SR. The Ca2+-induced Ca2+ release blocker ruthenium red (10 μmol/L) inhibited both caffeine- and eugenol-induced muscle contractions. Ryanodine (200 μmol/L), a specific ryanodine receptor/Ca2+ release channel blocker, promoted complete inhibition of the contractions induced by caffeine, but only partially blocked the contractions induced by eugenol. Heparin (2.5 mg/mL), an inositol 1,4,5-trisphosphate (InsP3) receptor blocker, strongly inhibited the contractions induced by eugenol but had only a small effect on the caffeine-induced contractions. Eugenol neither altered the Ca2+ sensitivity nor the maximal force in Triton X-100 skinned muscle fibers. These data suggest that muscle contraction induced by eugenol involves at least 2 mechanisms of Ca2+ release from the SR: one related to the activation of the ryanodine receptors and another through a heparin-sensitive pathway.

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