Histamine: A Neurotransmitter Candidate for Drosophila Photoreceptors
Article first published online: 5 OCT 2006
Journal of Neurochemistry
Volume 57, Issue 5, pages 1757–1768, November 1991
How to Cite
Sarthy, P. V. (1991), Histamine: A Neurotransmitter Candidate for Drosophila Photoreceptors. Journal of Neurochemistry, 57: 1757–1768. doi: 10.1111/j.1471-4159.1991.tb06378.x
- Issue published online: 5 OCT 2006
- Article first published online: 5 OCT 2006
- Received October 30, 1990; final revised manuscript received April 3, 1991; accepted April 22, 1991.
- Histidine decarboxylase;
: Recent experimental evidence suggests that histamine might be the synaptic transmitter used by invertebrate photoreceptors. In the present study, we have examined whether histamine is a transmitter candidate for Drosophila photoreceptors. Our findings are as follows; (a) Large amounts of histamine are synthesized by wild-type heads, whereas heads from the eye-deficient mutants, eyes absent and sine oculis, show reduced histamine synthesis, (b) Histidine de-carboxylase activity is ⋍ 10-fold higher in extracts of normal heads compared with that ia the mutants, (c) Histamine taken up by fly heads is metabolized into N-acetylhistamine and imidazole-4-acetic acid, (d) Immunostaining of normal and sevenless heads with histamine-specific antisera demonstrates that histamine is present in photoreceptors R1–6 and R8. (e) Histamine synthesized from exogenously supplied [3H]-histidine can be released by depolarization with 50 mM K+, and the release is Ca2+ dependent. These observations strongly suggest that histamine is a major neurotransmitter used by Drosophila photoreceptors.