scispace - formally typeset
Search or ask a question
Topic

Toad

About: Toad is a research topic. Over the lifetime, 1624 publications have been published within this topic receiving 28732 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: The presumption being that any departure from the Bell-Magendie law of the conduction of impulses will be associated with a corresponding exception to the Wallerian law of degeneration, the degeneration method has been given most attention.
Abstract: EXPERIMENTS made with the object of determining whether efferent fibres exist in the dorsal spinal nerve-roots of the frog have given contradictory results in the hands of different observers. On the one hand Steinach (1) finds that spinal nerves send viscero-motor fibres to the cesophagus, stomach and intestine solely by the dorsal roots, and to the rectum and bladder in part by the dorsal roots. On the other hand, Horton-Smith (2) found no evidence for the presence of viscero-motor fibres in the dorsal roots: but in a small percentage of cases he found that motor fibres to certain skeletal muscles were contained in the 7th, 8th or 9th dorsal root of one side. Wana (8), working under Steinach, has been able to observe this effect on skeletal muscles, though the number of cases in which it occurred was relatively smaller than in Horton-Smith's experiments. The above observations were all made by the method of stimulation, and it seemed better to attack the question by another method of experiment than simply to add to the tale of conflicting evidence. The presumption being that any departure from the Bell-Magendie law of the conduction of impulses will be associated with a corresponding exception to the Wallerian law of degeneration, I have given most attention to the degeneration method, though some experiments have also been made by the old method of stimulation. The results on certain points seem to be decisive, but I have been unable, for lack of time, to carry out the observations as fully as I had hoped.

13 citations

Journal ArticleDOI
TL;DR: The results suggest that, unlike its function in the rat, T4 in the toad does not regulate cellular thermogenesis by inducing Na+-K+-ATPase, which could account at least in part for the transition from poikilothermy to homeothermy.
Abstract: The effects of thyroxine (T4) on Na+ transport, oxygen consumption (QO2), and Na+-K+-ATPase activity were studied in the urinary bladder and liver of the toad Bufo marinus. In the bladder, T4 in vitro (10(-8) to 10(-6) M) had no significant effect on these parameters during 15 h of incubation. When injected intraperitoneally (approximately 20 microgram/(kg body wt.day) for 6 days), T4 lowered base-line, short-circuit current by 62% (P less than 0.0025) and potential difference by 37% (P less than 0.001), increasing tissue resistance by 40% (P less than 0.02). T4 depressed QO2/DNA (-25%, P less than 0.05) with no significant effect on Na+-K+-ATPase activity. In liver, T4 increased the recovery per cell DNA of mitochondrial proteins by 32% (P less than 0.025), corresponding to an increased QO2 (stage IV) of isolated mitochondria per cell DNA (+54%, P less than 0.01). There was no significant effect on Na+-K+-ATPase activity. These results suggest that, unlike its function in the rat, T4 in the toad does not regulate cellular thermogenesis by inducing Na+-K+-ATPase. This major difference could account at least in part for the transition from poikilothermy to homeothermy. In addition, T4 has a distinct inhibitory effect on Na+ transport in the urinary bladder, which suggests an antagonism to the action of aldosterone.

13 citations

Journal ArticleDOI
TL;DR: Data suggest that the effects of ACTH on habituation are, in part, independent of effects on glucocorticoid secretion, and similar structural requirements are necessary for the behavioral effects of melanocortins in amphibians and mammals.

13 citations


Network Information
Related Topics (5)
Endoplasmic reticulum
48.3K papers, 2.4M citations
77% related
Secretion
24.8K papers, 1.2M citations
75% related
Membrane potential
18.7K papers, 939.6K citations
75% related
Cytoplasm
19.8K papers, 942.8K citations
74% related
Golgi apparatus
19.8K papers, 1M citations
73% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202348
2022118
202112
202012
201913
20188