... a role. Using the northern leopard frog, Rana pipiens, we show here that injection of noradrenaline (norepinephrine) brings about a long-term depletion of skin peptides (initial concentrations do not recover until after day 56). When peptide stores recovered, the renewed peptides were similar...

... 280, Boston, MA, USA) was used to measure Ca 2+ and Mg 2+ levels and a standard kit for P i (Kit 670 Sigma, St Louis, MO, USA). Leopard frogs Rana pipiens Schreber 1782 (body mass 26.9-101.9 g),were obtained from Lemberger (Oshkosh, WI, USA). Frogs used in the anoxia,exercise and mineral...

... underlying among-individual variation in SMR. In a novel approach, we examine two potential proximate correlates of variation in SMR, in addition to organ mass,in leopard frogs Rana pipiens . We measured SMR of the frogs, then measured the masses of energetically expensive organs, serum-free T4 thyroxine...

... (DPIV) to quantify the flow structure of the wake produced by the feet during the propulsion phase of the kick of surface swimming frogs( Rana pipiens ). These frogs use two different gaits, asynchronous and synchronous kicking, and the magnitude of the thrust produced by the feet differs between...

... on the ascending limb of the force–length relationship. Twenty-nine stretch experiments on ten single fibres from the lumbrical muscle of the frog Rana pipiens were carried out on the ascending limb of the force–length relationship. Force enhancement was observed in 28 out of the 29 tests. Moreover, the force...

..., cineradiography, electromyography and nerve transection experiments to evaluate the contribution of eye retraction to swallowing in the northern leopard frog, Rana pipiens . Behavioral observations of frogs feeding on 1.5 cm long crickets reveal a high degree of variability in eye retraction and swallowing. Eye...

... and 3-4 h anoxic frog Rana pipiens , in order to determine whether their neurotransmitter responses resemble the anoxia-vulnerable or anoxia-tolerant response. Increases in whole brain serine, glycine, alanine and GABA levels were similar to those seen in anoxia-tolerant species, although the levels...

... of a realistic model of the frog Rana pipiens . We measured the anatomical properties of 13 proximal muscles in the frog hindlimb and incorporated these measurements into a set of musculotendon actuators. We examined whether the interaction between this musculotendon subsystem and a previously developed skeleton...

... may have evolved specifically to extend the limits of performance. Little is known about how the joints of the frog contribute to and limit jumping performance. To address these issues, we developed a skeletal model of the frog Rana pipiens that contained realistic bones, joints and body-segment...

...Gordon J. Lutz; Shannon N. Bremner; Michael J. Bade; Richard L. Lieber SUMMARY Isoforms of myosin heavy chain (MHC) and myosin light chain (MLC) influence contractile kinetics of skeletal muscle. We previously showed that the four major skeletal muscle fibre types in Rana pipiens (type 1, type 2...

... neuronal death. The few species that survive brain anoxia for days or months, such as the freshwater turtle Trachemys scripta , avoid anoxic depolarization and maintain brain ATP levels through a coordinated downregulation of brain energy demand processes. The frog Rana pipiens represents an intermediate...

... from the phylogenetically distinct leopard frog Rana pipiens . * e-mail: doeller@uab.edu 19 04 1999 22 06 1999 © 1999 by Company of Biologists 1999 Fig. 3. Measurements of Geukensia demissa gills (filled columns), Mytilus edulis gills (hatched columns...

...Peter L. Lutz; Raymond Reiners ABSTRACT This study investigated the relationship between energy failure and neurotransmitter release in the frog ( Rana pipiens ) brain during 1–3 h of anoxia. Unlike truly anoxia-tolerant species, the frog does not defend its brain energy charge. When exposed...

... play a role in maintaining the clustering of the nuclei. We describe the normal distribution of nuclei clustered in the synaptic region of intact adult frog, Rana pipiens , skeletal muscle fibers and show that innervation is not required to maintain the nuclear clusters. Even after long-term (4 week...

...Douglas A. Syme; Robert K. Josephson ABSTRACT The work capacity of segments of atrial and ventricular muscle from the frog Rana pipiens was measured as a function of muscle length using the work loop technique. Both the work done during shortening and the work required to re-lengthen the muscle...

...Nelson L. Daló; John C. Hackman; Kenneth Storey; Robert A. Davidoff ABSTRACT The effects of sudden cooling of the spinal cord were studied in three species of amphibians – a cold-sensitive tropical toad ( Bufo marinus ), a cold-resistant, aquatic, hibernating frog ( Rana pipiens , northern leopard...

...Daniel F. Stiffler ABSTRACT The frog Rana pipiens takes up Ca 2+ against an electrochemical gradient from dilute external solutions that are similar to natural freshwater environments. The influx is dependent upon external [Ca 2+ ] and is saturable. Kinetic analysis yielded a K m of 0.625 mmol l −1...

... leopard frog Rana pipiens freeze tolerance glucose metabolism Although amphibians live successfully in many different environments, their highly water-permeable skins mean that water balance is a constant challenge. Evaporative water loss is a major consideration in terrestrial environments...

...Douglas A. Syme ABSTRACT Mechanical power and oxygen consumption were measured simultaneously from isolated segments of trabecular muscle from the frog ( Rana pipiens ) ventricle. Power was measured using the work-loop technique, in which bundles of trabeculae were subjected to cyclic, sinusoidal...

...Curtis W. Anderson ABSTRACT Using high-speed video motion analysis, the kinematics of feeding behavior was studied in Rana pipiens. Rana pipiens exhibits differing behavior patterns depending upon prey type. When feeding on small prey such as waxworms, R. pipiens uses tongue protraction to catch...