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23. Agonistic behavior and courtship behavior of male crickets, Gryllus bimaculatus
348
Abstracts
received both colored axon terminals; that is, axons from both anterior and posterior branches of the antennal nerve. These results suggest that glomerular organization of the antennal lobe reflects the topographic map of the antennal sensory neurons on the antennae. doi:10.1016/j.cbpb.2007.07.057
20. Molecular mechanism of Mg2+ action on the FMRFamide-gated Na+ channel Yasuo Furukawa, Yu Kodani, Laboratory of Neurobiology, Grad. Sch. Integrated Arts & Sci., Hiroshima Univ., Higashi-Hiroshima, Hiroshima 739-8526, Japan
In Aplysia FaNaC (AkFaNaC) expressed in Xenopus oocytes, we previously showed that Ca2+ blocks but Mg2+ potentiates the FaNaC current [1]. It is also shown that Mg1002+ but not Ca2+ augments the desensitization [1]. Because divalent cations often interact with the pore region of ion channels, we examined a putative pore region of FaNaC and found two conserved aspartate residues (D552, D556) among molluscan FaNaCs. To address the functional roles of the aspartate residues, we made mutant channels by replacing the aspartate with either asparagine or cysteine. Although the D556 mutants did not express functional channels, the D552 mutants expressed robust FMRFamide-gated Na+ currents. In the D552 mutants, Mg2+ did not potentiate the current but rather blocked the current although the potency was much less than Ca2+ block. Ca2+ block was little affected by the mutation. Neither Ca2 + nor Mg2+ affects the desensitization of the mutants. These results suggest that D552 is a divalent binding site affecting the desensitization. The binding of Mg2+ to D552 may promote conformational change for the desensitization, whereas the binding of Ca2+ to the same site may inhibit the conformational change. [1] Furukawa, Miyawaki, Abe (2006), Pflugers Arch, 451:646–656. doi:10.1016/j.cbpb.2007.07.058
21. The initial study of ant’s (Formica japonica) selecting food Ayana Oku a, Masakatsu Ureshi b, a Kagoshima Prefect, Kajiki Elemen. Jr. HiSch. Handi. Child., Kagoshima 899-5241, Japan; b Dept. Sci. Math., Fac. Cult. Edu., Saga Univ., Saga 840-8502, Japan We investigated ant’s (Formica japonica) selecting of food. The three test solutions sweet (glucose), salt (NaOH) and bitter (quinine hydrochloride) were used, which were colored, respectively, by three food colors. We placed nine wells each solution, i.e., placed 27 (=9*3) wells, and three ants that had fasted more than 5 days in a laboratory dish. They were let eat freely for 5 h in the dark. Then, the ants were frozen by nitrogen liquid, and were homogenized after free eating. The frozen ants were then homogenized, put into 0.5 ml of 50% ethanol, and were measured by spectrophotometer. The results state that the sweet test solution was most eaten when it was 0.5 M and that the salt test solution was most eaten when it was 0.1 M. This result suggests that the ant’s selecting of food depends on the concentration of the solution. Moreover, the ant takes salt actively in every concentration. doi:10.1016/j.cbpb.2007.07.059
22. Physiological roles of nitric oxide in the cricket terminal abdominal ganglion Hiroto Ogawa a, Yoshichika Baba b, Yoshiichiro Kitamura c, Yoshichiro Kitamura c, Hitoshi Aonuma d, Kotaro Oka e, a Dept. Biol., Fac. Med., Saitama Med. Univ., Saitama 350-0496, Japan; b Dept. Biol. Sci., Coll. Liberal Arts & Sci., Univ. Illinois at Chicago, IL 60618, USA; c Fac. Pharmaceut. Sci. at Kagawa Campus, Tokushima Bunri Univ., Sanuki, 769-2193, Japan; d NeuroCybernetics Lab., RIES, Hokkaido Univ., Sapporo 060-0812, Japan; e Dept. Bioscience and Informatics, Fac. Sci. and Tech., Keio Univ., Yokohama, Japan
Nitric oxide (NO) acts as a neuromodulator in the central nervous system over various animal species. Recently, we identified possible NO-releasing and target neurons in the terminal abdominal ganglion (TAG) of the cricket using immunohistochemical analysis. Furthermore, direct measurement with an NO-specific electrode revealed that several hundreds nanomolar NO was basally produced in TAG, and that bath application of acetylcholine enhanced the NO production. However, the physiological role of NO in the specific neural circuit within TAG has been unknown. In the present study, we examine effects of NO synthase (NOS) inhibitor, L-NAME, on spiking activity of the ascending interneurons, of which cell bodies and dendrites were located within TAG and axons ascended into the connective nerve cord. In the saline containing L-NAME, both spontaneous firing and wind-evoked response slightly decreased in the ascending interneurons, but LNAME had no significant effect on their activities. However, if the cercal sensory circuit was disinhibited by GABAA-receptor antagonist, picrotoxin, L-NAME suppressed the wind-evoked responses and acuminated the directional selective properties of the ascending interneurons. NO production may be involved in the regulation of the directional sensitivity to the air current stimulus via modulation of non-GABAergic inhibitory pathways. doi:10.1016/j.cbpb.2007.07.060
23. Agonistic behavior and courtship behavior of male crickets, Gryllus bimaculatus Masazumi Iwasaki, Chihiro Katagiri, Lab. Biochem., Inst. Low Temp. Sci., Hokkaido Univ., Sapporo 060-0819, Japan
We have studied agonistic and courtship behaviors of male crickets; their key signals and modulation. Using the dorsal rim area of compound eyes, a male slowly approached the polarized structure of forewings of the opponent male. Then the male produced agonistic behavior by volatile substances from the opponent male and agonistic interaction between the two males started. After a loss, subordinate males avoided further contacts with the dominant male for up to 30 min. Three sequential losses prolonged this depression of aggressiveness in subordinate males for several hours and the head injection of NO signaling inhibitor canceled the depression of aggressiveness. Courtship behavior of males was induced by antennal contact stimulation using saturated cuticular hydrocarbons on the cricket body surface. Males avoided male unsaturated cuticular hydrocarbons. Our results indicate that: (1) polarized vision and volatile substances of male crickets initiate agonistic behavior of males; (2) the dominance between dominant and subordinate is maintained by the behavioral change of subordinate males, and NO signaling relates to this behavioral change; and (3) saturated cuticular hydrocarbons on the cricket body surface contain cricket sex pheromones. doi:10.1016/j.cbpb.2007.07.061
24. Ca2+ imaging of ascidian larvae with a Ca2+ indicator protein, Cameleon Masashi Nakagawa a, Takehiro Kusakabe a, Yasunori Sasakura b, Atsushi Miyawaki c, a Grad. School of Life Sci. Univ. Hyogo, Koto 3-2-1, Akoh, Hyogo 678-1297, Japan; b Shimoda Marine Research Center, Univ. Tsukuba, 5-10-1 Shimoda, Shizuoka 415-0025, Japan; c Brain Sci. Inst. RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
Ascidians are the closest living relatives of vertebrates. The tadpole larva is composed of only 2600 cells. Especially, the central nervous system is constructed from about 100 nerve cells. The simple body makes an ascidian larva to be a fascinated model animal for vertebrates. However, the physiological study on ascidian larva has not so progressed. It is because the cells are too small and the whole body is covered with the tunic, which makes electrophysiological methods difficult to apply. Thus, we tried an optical imaging technique. Cameleon is a calcium indicator fluorescent protein and it
Abstracts
received both colored axon terminals; that is, axons from both anterior and posterior branches of the antennal nerve. These results suggest that glomerular organization of the antennal lobe reflects the topographic map of the antennal sensory neurons on the antennae. doi:10.1016/j.cbpb.2007.07.057
20. Molecular mechanism of Mg2+ action on the FMRFamide-gated Na+ channel Yasuo Furukawa, Yu Kodani, Laboratory of Neurobiology, Grad. Sch. Integrated Arts & Sci., Hiroshima Univ., Higashi-Hiroshima, Hiroshima 739-8526, Japan
In Aplysia FaNaC (AkFaNaC) expressed in Xenopus oocytes, we previously showed that Ca2+ blocks but Mg2+ potentiates the FaNaC current [1]. It is also shown that Mg1002+ but not Ca2+ augments the desensitization [1]. Because divalent cations often interact with the pore region of ion channels, we examined a putative pore region of FaNaC and found two conserved aspartate residues (D552, D556) among molluscan FaNaCs. To address the functional roles of the aspartate residues, we made mutant channels by replacing the aspartate with either asparagine or cysteine. Although the D556 mutants did not express functional channels, the D552 mutants expressed robust FMRFamide-gated Na+ currents. In the D552 mutants, Mg2+ did not potentiate the current but rather blocked the current although the potency was much less than Ca2+ block. Ca2+ block was little affected by the mutation. Neither Ca2 + nor Mg2+ affects the desensitization of the mutants. These results suggest that D552 is a divalent binding site affecting the desensitization. The binding of Mg2+ to D552 may promote conformational change for the desensitization, whereas the binding of Ca2+ to the same site may inhibit the conformational change. [1] Furukawa, Miyawaki, Abe (2006), Pflugers Arch, 451:646–656. doi:10.1016/j.cbpb.2007.07.058
21. The initial study of ant’s (Formica japonica) selecting food Ayana Oku a, Masakatsu Ureshi b, a Kagoshima Prefect, Kajiki Elemen. Jr. HiSch. Handi. Child., Kagoshima 899-5241, Japan; b Dept. Sci. Math., Fac. Cult. Edu., Saga Univ., Saga 840-8502, Japan We investigated ant’s (Formica japonica) selecting of food. The three test solutions sweet (glucose), salt (NaOH) and bitter (quinine hydrochloride) were used, which were colored, respectively, by three food colors. We placed nine wells each solution, i.e., placed 27 (=9*3) wells, and three ants that had fasted more than 5 days in a laboratory dish. They were let eat freely for 5 h in the dark. Then, the ants were frozen by nitrogen liquid, and were homogenized after free eating. The frozen ants were then homogenized, put into 0.5 ml of 50% ethanol, and were measured by spectrophotometer. The results state that the sweet test solution was most eaten when it was 0.5 M and that the salt test solution was most eaten when it was 0.1 M. This result suggests that the ant’s selecting of food depends on the concentration of the solution. Moreover, the ant takes salt actively in every concentration. doi:10.1016/j.cbpb.2007.07.059
22. Physiological roles of nitric oxide in the cricket terminal abdominal ganglion Hiroto Ogawa a, Yoshichika Baba b, Yoshiichiro Kitamura c, Yoshichiro Kitamura c, Hitoshi Aonuma d, Kotaro Oka e, a Dept. Biol., Fac. Med., Saitama Med. Univ., Saitama 350-0496, Japan; b Dept. Biol. Sci., Coll. Liberal Arts & Sci., Univ. Illinois at Chicago, IL 60618, USA; c Fac. Pharmaceut. Sci. at Kagawa Campus, Tokushima Bunri Univ., Sanuki, 769-2193, Japan; d NeuroCybernetics Lab., RIES, Hokkaido Univ., Sapporo 060-0812, Japan; e Dept. Bioscience and Informatics, Fac. Sci. and Tech., Keio Univ., Yokohama, Japan
Nitric oxide (NO) acts as a neuromodulator in the central nervous system over various animal species. Recently, we identified possible NO-releasing and target neurons in the terminal abdominal ganglion (TAG) of the cricket using immunohistochemical analysis. Furthermore, direct measurement with an NO-specific electrode revealed that several hundreds nanomolar NO was basally produced in TAG, and that bath application of acetylcholine enhanced the NO production. However, the physiological role of NO in the specific neural circuit within TAG has been unknown. In the present study, we examine effects of NO synthase (NOS) inhibitor, L-NAME, on spiking activity of the ascending interneurons, of which cell bodies and dendrites were located within TAG and axons ascended into the connective nerve cord. In the saline containing L-NAME, both spontaneous firing and wind-evoked response slightly decreased in the ascending interneurons, but LNAME had no significant effect on their activities. However, if the cercal sensory circuit was disinhibited by GABAA-receptor antagonist, picrotoxin, L-NAME suppressed the wind-evoked responses and acuminated the directional selective properties of the ascending interneurons. NO production may be involved in the regulation of the directional sensitivity to the air current stimulus via modulation of non-GABAergic inhibitory pathways. doi:10.1016/j.cbpb.2007.07.060
23. Agonistic behavior and courtship behavior of male crickets, Gryllus bimaculatus Masazumi Iwasaki, Chihiro Katagiri, Lab. Biochem., Inst. Low Temp. Sci., Hokkaido Univ., Sapporo 060-0819, Japan
We have studied agonistic and courtship behaviors of male crickets; their key signals and modulation. Using the dorsal rim area of compound eyes, a male slowly approached the polarized structure of forewings of the opponent male. Then the male produced agonistic behavior by volatile substances from the opponent male and agonistic interaction between the two males started. After a loss, subordinate males avoided further contacts with the dominant male for up to 30 min. Three sequential losses prolonged this depression of aggressiveness in subordinate males for several hours and the head injection of NO signaling inhibitor canceled the depression of aggressiveness. Courtship behavior of males was induced by antennal contact stimulation using saturated cuticular hydrocarbons on the cricket body surface. Males avoided male unsaturated cuticular hydrocarbons. Our results indicate that: (1) polarized vision and volatile substances of male crickets initiate agonistic behavior of males; (2) the dominance between dominant and subordinate is maintained by the behavioral change of subordinate males, and NO signaling relates to this behavioral change; and (3) saturated cuticular hydrocarbons on the cricket body surface contain cricket sex pheromones. doi:10.1016/j.cbpb.2007.07.061
24. Ca2+ imaging of ascidian larvae with a Ca2+ indicator protein, Cameleon Masashi Nakagawa a, Takehiro Kusakabe a, Yasunori Sasakura b, Atsushi Miyawaki c, a Grad. School of Life Sci. Univ. Hyogo, Koto 3-2-1, Akoh, Hyogo 678-1297, Japan; b Shimoda Marine Research Center, Univ. Tsukuba, 5-10-1 Shimoda, Shizuoka 415-0025, Japan; c Brain Sci. Inst. RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
Ascidians are the closest living relatives of vertebrates. The tadpole larva is composed of only 2600 cells. Especially, the central nervous system is constructed from about 100 nerve cells. The simple body makes an ascidian larva to be a fascinated model animal for vertebrates. However, the physiological study on ascidian larva has not so progressed. It is because the cells are too small and the whole body is covered with the tunic, which makes electrophysiological methods difficult to apply. Thus, we tried an optical imaging technique. Cameleon is a calcium indicator fluorescent protein and it