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アカガエル上科(Ranoidea)に分類される，ヌマガエル科(Dicroglossidae)のヌマガエル(Fejervarya kawamurai)，アカガエル科(Ranoidae)のトノサマガエル(Pelophylax nigromaculatus)，ナゴヤダルマガエル(Pelophylax porosus brevipodus)，ウシガエル(Lithobates catesbeianus)，ヤマアカガエル(Rana ornativentris)，ニホンアカガエル(Rana japonica)，タゴガエル(Rana tagoitagoi)，ツチガエル(Glandirana rugose)，およびアオガエル科(Rhacophoridae)のモリアオガエル(Rhacophorus arboreus)，シュレーゲルアオガエル(Rhacophorus schlegelii)の水晶体でρ-クリスタリンタンパク質の発現が確認された。アマガエル上科(Hyloidea)に分類されるアマガエル科(Hyloidae)のニホンアマガエル(Hyla japonica)およびアカメアマガエル(Agalychnis callidryas)の水晶体においてζ-クリスタリンタンパク質の発現が確認された。また，アマガエル上科における，ツノガエル科(Ceratophryidae)のクランウエルツノガエル(Ceratophrys cranwelli)，ヒキガエル科(Bufonidae)のアズマヒキガエル(Bufo ｊaponicas formosus)，ナガレヒキガエル(Bufo torrenticola)，テキサスヒキガエル(Bufo speciosus)，およびヤドクガエル科(Dendrobatidae)のコバルトヤドクガエル(Dendrobates azureus)，キオビヤドクガエル(Dendrobates leucomelas)の水晶体にはいずれの種特異的クリスタリンタンパク質も検出できなかった。

Symposium for Women Researchers (SWR), 東京, 第7回, 東京都立戸山高等学校

Food habits of seven frog species during mating periods were examined from gastric contents and species comparison were conducted. From 1041 frogs, elementary information on their food habits such as species and sizes of prey insects were reported and species difference and sex difference were discussed. Males of Tago's brown frogs (Rana tagoi ) and Shlegel's green tree frogs (Rhacophorus schlegelii ) foraged nothing during mating periods as previous reports, but males of the other five species did. Males of Japanese tree frogs( Hyla japonica) and Japanese stream frogs( Buergeria buergeri) were getting to forage towards the end of their mating periods. Especially, male black spotted pond frogs( Rana nigromaculata ) seemed to prefer larger insect than expected from their environment food resources, foraged well and gained their body weight during mating periods. These species differences seem to be caused mainly from their length of mating periods and their extent of site fidelity in mating periods.

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To investigate the relationship between gravity and the thyroid hormone on the pituitary-thyroid axis of amphibians, we raised frogs, Xenopus tropicana under hypergravity (5G) environment and gave thyroxin from St58 to St 59-60. The development of the frog was delayed under hypergravity condition. The total volume, cell size and cell number were reduced in pituitary, thyroid and cerebellum of hypergravity treated frogs. On the other hand, the morphological malfunctions of the treated frogs were recovered by the administration of thyroxin. These changes indicate that the drug recovers the declined functions. These results suggest that the thyroxin therapy rescues the hypofunction and dysfunction of the pituitary-thyroid axis from hypergravity., 資料番号: AA0063706064

Because of many advantages, amphibians have been important experimental models in space utilization research. However, the results of previous space experiments with Xenopus laevis suggested that the larval growth was retarded or abnormal in the microgravity environment. It was supposed that Xenopus larvae could not recognize the air position in microgravity and failed to inflate their lungs in an appropriate manner during the critical period of lung development. In this study, ground-based experiments and parabolic flight experiments were made to form a stable air-water interface and keep its position for a while, and also to investigate whether Xenopus larvae can recognize the generated air-water interface by using an illumination as a cue, in microgravity achieved by parabolic flight. It was concluded that it will be possible to generate stable air-water interface even in the microgravity environment by using the 'air stabilizer', and Xenopus larvae will recognize the position of artificially formed water surface and breathe the air properly if they are illuminated from the same direction with the generated air-water interface., 資料番号: AA0063706066

Our previous studies revealed that application of tap water to the oral mucosa of the frog elicits an oral reflex in which rhythmical movements of buccal respiration cease and the buccal pressure rises. To demonstrate the pathway and central mechanism of this reflex, we studied reflex neural discharges of the trigeminal nerve elicited by electrical stimulation of the glossopharyngeal nerve using brain stem preparations in vitro. Removal of the cerebellum did not eliminate the reflex discharge. Dissecting the ipsilateral wall of the medulla oblongata close to the glossopharyngeal nerve terminal eliminated the reflex discharge. The findings indicate that the cerebellum is not related to the reflex, and the proximal, but not the caudal, region of the solitary nucleus is essential for the reflex.

Our previous studies revealed that application of tap water to the oral mucosa in the frog elicits the oral reflex in which rhythmical movements of buccal respiration are depressed and the buccal pressure is elevated. In order to examine the pathway and central mechanism of this reflex, we studied the neural discharges in the brain stem elicited by water stimulation of the palatal mucosa and by simultaneously applied electrical stimulation of the glossopharyngeal, facial and trigeminal nerves. Among 33 neurons whose activity was recorded from the ventral side of the brain stem, three were motoneurons and nine were presumed to be premotoneurons, but 20 were of unidentified types. The interneurons with recorded activity were located lateral to the trigeminal motor nucleus and medial to the facial nucleus. No interneuron activity was observed in the caudal part of the brain stem.

ウシガエル交感神経節細胞にカフェインを投与すると細胞膜の電位の振動(RMH:Ca2+activatedGk+)が発現する.この応答の機序をCa2+イオンチャンネル阻害剤や局所麻酔剤を用いて検討した.Ca2+チャンネル阻害剤ライアノジンおよびライアノジン誘導体によってRMHは非可逆的に阻害された.CICR阻害剤プロカインによって可逆的に阻害された.局所麻酔剤コカイン投与によってRMHは阻害されたが,同リドカインではほとんど阻害されなかった.プロカインで阻害されたカフェイン誘導RMHはATP,ADPの投与でコントロールレベルまで回復したが,アデノシン,C-AMP,C-GMPでは回復しなかった.以上より,交感神経節細胞にも筋細胞に存在するCICR機構が存在することが示唆された

Chemical modification of protein was applied to a frog water receptor to learn whether or not sulfhydryl and amino residues are indispensable to the receptor site of Ca response. N-ethylmaleimide (NEM), which is known to modify sulfhydryl residues of protein, was shown to inhibit Ca response irreversibly without affecting responses of tactile receptors, indicating that the recepter molecule responsible for Ca response is protein. Trinitrobenzene sulfonate (TNBS) and β-naphthoquinone-4-sulfonate (NQS), which are known to modify amino residues of protein, did not inhibit Ca response irreversibly, indicating that amino residues are not indispensable to the receptor site of Ca response.

N-bromosuccinimide, which is known to act on histidine and tryptophan residues of polypeptides and proteins, has been shown to inhibit Ca response specifically without inhibiting Na response in the water receptor of the frog. In order to ascertain the involvement of histidine and tryptophan residues in the receptor site responsible for Ca response, effects of histidase, tryptophanase and α-chymotrypsin on Ca and Na responses were examined. Histidase , tryptophanase and α-chymotrypsin inhibited Ca response without inhibiting Na response, while tyrosinase had no effect on either Ca nor Na response. These results suggest that the receptor site for Ca response involves histidine and/or tryptophan residues.

Cell-cell adhesion and cell polarity is an essential cue for proper cell differentiation. We identified Makorin1 as an important regulator which senses signals from cell surface and transduces signals into the nucleus. Makorin1 is localized at the cell membrane and in the nucleus, which dynamically change the position depending on the stimulation. Makorin1 mutants displayed various developmental defects including osteogenesis impairment, nephorgenesis and skin defect. Here, we report how Makorin1 regulates gene expression., 資料番号: AA0063706062

In order to reveal the role of the ATP hydrolyzing enzyme in the mucous membrane of the frog tongue test solutions containing ATP were applied to the tongue surface of intact frogs. The ATP of the solutions was found to be hydrolyzed proportionally to the number of application, indicating that the active sites of the ATP hydrolyzing enzyme is exposed in the oral cavity. Some properties of the ATP hydrolyzing enzyme were also studied.

In order to characterize the types of motor units operating upon tonic jaw reflexes in the frog, the properties of the jaw muscles operating upon the nostril-closing reflex were examined histochemically and physiologically. In addition, the properties of motoneurons were examined by the firing pattern, firing rate, duration and some other characteristics of their efferent neural discharges during the reflex. The results are as follows: (1) Muscular contractions during the reflex were basically tonic, but these were sometimes accompanied by phasic contractions. (2) Histochemistry of myofibrillar ATPase and succinic dehydrogenase (SDHase) activities revealed that the nostril-closing (submental, submaxillary, masseter and pterygoid) muscles contain at least two types of muscle fibers. One type exhibited high alkaline-stable myosin ATPase and low SDHase activities, and the other type exhibited low alkaline-stable myosin ATPase and high SDHase activities. Muscle fibers with acid-stable myosin ATPase activity were prevalent in the pterygoid muscle, scarce in the submental and masseter muscles, and absent in the submaxillary muscle. (3) In pottasium contractures of muscle strips made from the submaxillary muscle, muscle strips consisting of muscle fibers with low alkaline-stable myosin ATPase and high SDHase activities exhibited a prolonged contraction, while those consisting of muscle fibers with high alkaline-stable myosin ATPase and low SDHase activities exhibited a transient contraction. This indicates that the former muscle strips were composed of tonic muscle fibers and the latter were composed of twitch muscle fibers. Comparison of tetanic contractions between both the muscle strips supported the same conclusion. (4) Variation in the appearance of the reflex discharges enabled a rough division of motoneurons into phasic, intermediate, and tonic types. Some motoneurons could not be classified, however. Based on these results, the mechanism of motor control in tonic jaw reflexes is discussed.

Electromyographic activities of jaw and tongue muscles produced reflexly by mechanical and chemical stimulation of various loci of orofacial region were studied in the frog, Rana nigromaculata. Temporal muscle activity occurred when mechanical stimuli were applied to the palatal ridge, lower lip, root of tongue and pharynx. Electromyograms of the masseter muscle were similar to that of the temporal muscle, but the masseter muscle activity was occurred ipsilaterally and was not occurred by the stimulation of the pharynx region. No activity of the mandible depresser muscle was obtained whatever portions of the mouth were stimulated, but a strong pinch of tongue tip generated a transient activity. A remarkable activity of the submaxillary muscle was observed when the pharynx region was stimulated mechanically. This muscle activity occurred synchronously with the respiration, and was suppressed by the mechanical stimulation of the oral mucosa except the tongue surface. The hyoglossal and intrinsic tongue muscles were activated by the mechanical and chemical stimulation of the tongue. The latter muscle was also activated by the mechanical stimulation of the pharynx region. These results are similar to those obtained in the higher vertebrates, suggesting that the neural mechanism of oral reflexes in the frog is fundamentally the same as those in the higher vertebrates.

Reflex neural discharges recorded in the branch of the trigeminal nerve innervating the submental muscle, following electrical stimulation of the glossopharyngeal nerve, exhibited temporal facilitation, after-discharge and fluctuant long latency, whereas those recorded in the hypoglossal nerve did not. These facts suggest that the reflex pathway of the nostrilclosing reflex is more complicated than that of the linguo-hypoglossal reflex in the frog.

The innervation of the facial nerve in the lower jaw of the frog was studied by recording afferent neural discharges from the submandibular branch of the facial nerve, and the effect of the nerve branch was then studied by comparing reflex discharges before and after dissection of the glossopharyngeal nerve. Receptive fields of the submandibular branch of the facial nerve were located in the mucosal part of the mandible and in the basal part of the tongue. By comparing the numbers of impulses between neural discharges in the glossopharyngeal and facial nerves, the magnitude of response in the submandibular branch of the facial nerve was found to be from 1/3 to 1/6 of that in the glossopharyngeal nerve. The effect of the submandibular branch of the facial nerve on nostril-closing reflex did not appear to be large.

In order to reveal neural mechanism of oral reflexes in the frog, we studied the reflex discharges of jaw-closing muscles or efferent nerves, and of the hypoglossal nerve elicited by electrical stimulation of the trigeminal, facial and glossopharyngeal nerves, and found that the main reflex discharges were sometimes preceded by a reflex discharge with short latency. Since the central delay of the reflex discharges with short latency, obtained by reducing conduction times in both the efferent and afferent nerves from the reflex latency, were less than 1 msec, the pathway of the reflex seemed to be monosynaptic. To make sure of this possibility, we studied unit discharges of trigeminal motoneurons by means of glass microelectrode recording, and found that some motoneurons elicit an action potential or an EPSP with short latency. These results indicate that some of the jaw-closing and tongue reflex pathways are monosynaptic.

Properties of alkaline phosphatase activity in the mucous membrance of the frog tongue were studied by applying test solutions containing β-glycerophosphate to the tongue surface of intact frogs. The properties of the alkaline phosphatase activity was found to be different from the properties of the ATPase activity described in the previous paper, suggesting both the ATPase and the alkaline phosphatase being different enzymes.

In order to reveal the information processing mechanism of gustation in the brain, the input-output relation in frog gustatory linguo-hypoglossal reflexes was studied. The mean number of impulses obtained from the experiments with single fungiform papilla preparations and the mean amplitude of integrated reflex responses obtained from the experiments with unanesthetized frogs were employed as the magnitudes of input and output information, respectively. The slope of the curve of input-output relation obtained was not so steep, indicating that the pathway of frog gustatory linguo-hypoglossal reflexes may be relatively simple, probably disynaptic.