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The unusual polyamines, sym-homospermidine (homoSPD) and canavalmine (CAN), were found in the seed of Canavalia species such as C. gladiata, C. ensiformis, and C. brasilensis, but not in those of other leguminous crops. To examine the distribution and metabolism of homoSPD and CAN in sword bean, C. gladiata cv Shironata, polyamine analysis was carried out throughout the life cycle of this plant. During seed germination, putrescine (PUT), spermidine (SPD), and spermine (SPM) were accumulated in the radicle and hypocotyl. HomoSPD and CAN were, however, maintained at very low levels over a 6-day period of germination. In nodulated sword bean plants, a large quantity of homoSPD was found in the root nodule. CAN was detected exclusively in the senescent nodule at very low concentrations. These polyamines were not detected in any other organs including root, stem, leaf, vine, flower, and pod, while PUT, SPD, and SPM were always found in those organs. As plants reached the reproductive stage, homoSPD and CAN appeared in the immature seed and their concentrations increased as seed formation progressed. By contrast, the level of SPM continuously decreased during seed development. In developing seeds, considerable accumulation of canavanine, an analog of arginine, which is a precursor in polyamine biosynthesis, was also observed.The aliphatic polyamines, PUT,' SPD, and SPM, occur ubiquitously in living organisms. These organic polycations are known to be involved in various cellular metabolic processes including synthesis of proteins and nucleic acids (1). The physiological and biochemical significance of polyamines in plant growth and development has recently been reviewed (21,24). In addition to the widespread usual polyamines, structural analogs, in which the length of methylene chain or the arrangement of aliphatic groups in the amines differs from the usual polyamines, have been found in certain organisms (19). Hamana and Matsuzaki (10) proposed that these unusual polyamines could serve as chemical phylogenic and taxonomic markers. Recently, we found two unusual polyamines, homoSPD and CAN, in the seed of sword bean Canavalia gladiata (5). HomoSPD, NH2(CH2)4NH(CH2)4NH2, has been found in a wide variety of organisms such as bacteria (11,18,22,26), algae (10, 20), lower and higher plants (15,28,29), and certain vertebrates (14,17 (7,8). The mechanism of biosynthesis and the potential role of these rare polyamines in plants, however, remain to be worked out. The present paper describes the distribution and metabolism ofhomoSPD and CAN throughout the growth period of sword bean plants (C. gladiata cv Shironata). The occurrence of polyamines in various leguminous seeds, including other species of Canavalia, has also been demonstrated. MATERIALS AND METHODS Plant Materials. A variety of leguminous seeds includingGlycine max, Phaseolus angularis, P. mungo, P. vulgaris, P. lunatus, Pisum sativum, Vicia faba, Vigna sinensis, Arachis hypogaea, Dolicos lablab, and Canavalia gladiata were supplied by the Seed Storage Lab...

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Abstract-Nicotine (0.5 and 1.0 mg/kg) administered subcutaneously to mice decreased the ambulatory activity recorded by an ambulo-meter in a dose-dependent manner from 5 to 60 min after the administration, and the higher dose (1.0 mg/kg) caused a long-lasting ataxia. To be noted was the initial increment of ambulation which usually preceded the ataxia-inducing effect with every dose of nicotine, and the lowest dose (0.10 mg/kg) employed herein induced only the increasing effect on ambulation recorded for the first 20 min after its administration. The ataxia inducing effect of nicotine (1.0 mg/kg) was attenuated by the pretreatment with mecamylamine (0.4-2.0 mg/kg) in a dose-dependent manner, though the at tenuating effect waned at a higher dose (4.0 mg/kg). In contrast, pretreatment with either hexamethonium (2.5 and 5.0 mg/kg) or atropine (1.0, 2.5 and 5.0 mg/ kg) did not affect the ataxia-inducing effect of nicotine. Atropine when adminis tered alone was found to markedly increase the ambulatory activity at the doses used for the pretreatment. Measurement of the time-dependent change of[3H]-nicotine level in brain tissue after its subcutaneous injection revealed that there is a good correlation between the brain levels of the alkaloid and the intensity of its ataxic effect rather than the initial increasing effect on ambulation. The results obtained herein suggest that nicotine exerts its ataxic effect centrally, but the site and type of the receptor stimulated by nicotine remains to be identified.