Summary 1. A study was carried out of the effect of caffeine and low temperature on smooth muscle of the toad bladder. 2. Spontaneous rhythmic contraction of smooth muscle is suppressed by the action of caffeine. 3. Rapid cooling elicits muscle contraction. Although spontaneous rhythmic contraction of the smooth muscle disappears with the application of caffeine, contraction is elicited by a rapid cooling treatment. 4. Unlike skeletal muscle, smooth muscle does not contract with upon repeated rapid cooling. 5. When caffeinized muscle, immersed in Ringer's solution, of which part of the sodium has been replaced with an equivalent amount of sucrose, is subjected to rapid cooling, the tension of the muscle increases in proportion to the amount substituted.There are two ways in which skeletal muscle fibers respond to caffeine. A low concentration of caffeine enhances muscle twitch tension, while high concentration produces muscle contracture (SANDOW, 1965).In 1958, AXELSSON and THESLEFF demonstrated that a skeletal muscle fiber immersed in Ringer's solution was made to contract by adding caffeine to the solution and that this effect was limited to the external surface of the muscle fiber, and caused no change in the membrane potential. Since their experiments, many investigators have attempted to clarify whether caffeine may, after all, act on inner structures of the muscle cell, such as the sarcoplasmic reticulum.According to HERZ and WEBER (1965), WEBER et al., (1966) and WEBER and HERZ (1968, when the concentration of the caffeine applied to Ringer's solution exceeds 5 mM, Ca is released from the sarcoplasmic reticulum, and its uptake is prevented. CONWAY and SAKAI (1960) and SAKAI (1962SAKAI ( , 1965 reported that skeletal muscle fibers were made to contract by rapid cooling, after they were treated with caffeine at less than 2 mM concentration. This phenomenon was
Gerlach (3) first noticed the presence of muscle fibers, capable of contracting by electrical stimulation, in the lymph glands. Rhythmic contractions of lymph glands were suggested by Heller (6). Harvey (4) and later Rous (8, 9) stated that pilocarpine caused contractions of the lymph glands. Florey (2) stated that the isolated mesenteric lymph glands of cats contracted with adrenaline and barium chloride, but not with pilocarpine, and that there was an increase in the number of leucocytes issuing from the mesenteric lymph glands when the mesenteric nerves were stimulated. Drinker (1), however, noticed that the perfused popliteal lymph glands of dogs did not contract by adrenaline. Hellman (7) was of opinion that contractions of the muscle fibres in the lymph
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