Abstract
It is well established that nitric oxide (NO) is an important neurotransmitter in the nervous system of mammals and insects. But the role of NO in the endocrine system is not clear. In mammals, NO is known to play an important role in the modulation of endocrine functions, but there is little study about NO in insect endocrine system until now. The corpous allatum (CA), an important endocrine gland producing juvenile hormone (JH) in insect, is considered the analogue of the anterior pituitary gland of vertebrates. While the CA has been shown to be the release site for several neuropeptides from brain neurosecretory cells, it is generally believed that JH is the only product synthesized and released from CA cells involving in regulation of insect growth, metamorphosis and reproduction. Previously, our lab has reported histochemical staining of NADPH diaphorase activities in CA cells of Diploptera punctat, Blattella germanica, Periplaneta americana and Leucania loreyi, but it can not directly prove the occurrence of nitric oxide synthase in CA cells. Here, I use NADPH diaphorase histochemistry、NOS immunostaining and one tube RT-PCR to demonstrate that indeed there is NOS expression in the CA cells of the third-instar larva of the fruit fly, Drosophila melanogaster. In addition, we observe the distribution of NOS expressing cells in the CNS of the fruit fly, Drosophila melanogaster, and discuss what is the role of these cells.