title: Immunocytochemical localization of amines and GABA in the optic lobe of the butterfly, Papilio xuthus.
abstract: Butterflies have sophisticated color vision. While the spectral organization of the compound eye has been well characterized in the Japanese yellow swallowtail butterfly, Papilio xuthus, neural mechanisms underlying its color vision are largely unexplored. Towards a better understanding of signal processing in the visual system of P. xuthus, we used immunocytochemical techniques to analyze the distribution of transmitter candidates, namely, histamine, serotonin, tyramine and γ-aminobutyric acid (GABA). Photoreceptor terminals in the lamina and medulla exhibited histamine immunoreactivity as demonstrated in other insects. The anti-histamine antiserum also labeled a few large medulla neurons. Medulla intrinsic neurons and centrifugal neurons projecting to the lamina showed serotonin immunoreactivity. Tyramine immunostaining was detected in a subset of large monopolar cells (LMCs) in the lamina, transmedullary neurons projecting to the lobula plate, and cell bodies surrounding the first optic chiasma. An anti-GABA antiserum labeled a subset of LMCs and populations of columnar and tangential neurons surrounding the medulla. Each of the four antisera also labeled a few centrifugal neurons that innervate the lobula complex from the central brain, suggesting that they have neuromodulatory roles. A distinctive feature we found in this study is the possibility that tyramine and GABA act as transmitters in LMCs of P. xuthus, which has not been reported in any other insects so far.
authors: Laboratory of Neuroethology, Sokendai, The Graduate University for Advanced Studies, Shonan Village, Hayama, Kanagawa, Japan.
authors: Yoshitaka
authors: Y
authors: Hamanaka
authors: Michiyo
authors: M
authors: Kinoshita
authors: Uwe
authors: U
authors: Homberg
authors: Kentaro
authors: K
authors: Arikawa
mesh_terms: D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism*; D002080:Butterflies / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D055253:Color Vision; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D009474:Neurons / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009899:Optic Lobe, Nonmammalian / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D015306:Biogenic Monoamines; D018377:Neurotransmitter Agents; D005680:gamma-Aminobutyric Acid