Camponotus Japonicus (ants) In The Brain 5 - Serotonergic Neuron Distribution In The Study

Using Colophony-Paraffin (CP) embedding tissue section technique and immunohistochemical streptalidin-peroxidase (SP) method, we have investigated the distribution of 5-HT neurons in the brain of Camponotus japonicus (big worker ant), compared the immunoreactivity with GABA, and primarily discussed the character of 5-HT distribution. The results show that 5-HT immunoreactive processes originate from a relatively small number of cell bodies but each neuron has processes over a large volume of the neuropil of the brain. The optic lobs and the central body are stained most deeply. All neuropil regions of optic lobe, the lamina, medulla and lobula, contain 5-HT immunoreactive varicose fibers, which are distinct in morphology and degree of staining. These all show pronounced stratification. There are three kinds of neurons related to the optic lobes: amacrine cells, columnar neurons and tangential neurons, only a few of which are stained. The labeling of the central body is deeply, and there is no obvious difference in the staining degree between upper central body and lower central body. Kenyon cells are not labeled. In the back of the protocerebrum, there are two groups (about 20) of large positive neurons whose axons often run in bundles, some thin branches of which invade a large area of the protocerebrum. The mushroom bodies show 5-HT immunoreactivity, whose components are distinct in the degree of the staining. The staining of the calyces are lighter than that of the pedunculus and a - lobes were deeper than P - lobes. Most of the 5-HT fibers of the a -lobes apparently are main branches of thick fibers which surrounded the a -lobes . All olfactory glomeruli are labeled and many 5-HT immunoreactive varicose fibers scattered within the center region of the olfactory lobe. Only one pair of neurons are labeled in antennal lobes. The antennal-cerebral tracts are stained light, except for the middle antennal-cerebral tract which show obvious 5-HT immunoreactivity. On the edge of the subosophageal about 10 neurons whose fibers formed 3 thick bundles are labeled. And the fibers distribute extensivly in the subosophageal.The result implies that 5-HT is an important neurotransmitter in the brain of Camponotus japonicus . 5-HT plays a role in mediating sensory system, learn and memory system, the activities of motor system as well. 5-HTimmunoreactive processes originate from a relatively small number of cell bodies, but each neuron having processes over a large volume of the brain, from which we can confer that 5-HT is important in mediating distant neural interactions.The result and analysis offer academic foundation to the research concerning learn and accumulates scientific information for the development of neurobiology.