Morphology Of Antennal Lobe Neurons In The Cotton Bollworm Helicoverpa Armigera

Antennal lobe is the primary olfactory center of insects.It receives the environmental odorant information from the periphery olfactory organs such as antenna,maxillary palp or labial palp,and transfers it to the higher nervous center after primary processing and integration.Then the higher nervous center exports behavioral conmands to guide relevant behaviors.The functions of antennal lobe are based upon the morphologies of its neurons,the kinds of neurotransmitters,and the connections among the neurons.Therefore,it is important to study the morphologies of antennal lobe neurons deeply for exploring their functions.In this research,we studied the morphologies of Helicoverpa armigera's antennal lobe neurons by the methods of intracellular recording and stain,immunohistology,laser scanning confocal microscope and analysis by related software.The results are as fellow:In the antennal lobe of Helicoverpa armigera,we labeled four typical types antennal lobe neurons,as the olfactory receptor neurons(ORNs),projection neurons(PNs),local neurons(LNs)and centrifugal neurons(CNs).In the ORNs,most of them fellow the hypothesis of one ORN targets its axon to one glomerulus.Except only several of them tragets 2 or 3 glomeruli or targets axonx in the antennal lobe and the gnathal ganglia.In the PNs,they are classified as uniglomerular PNs(uPNs),and multiglomerular PNs(mPNs).In the uPNs,the dendrites dominate one glomerulus,the somata locate in the lateral cell cluster or medial cell cluster,the axons project to the higher nervous center via the medial antennal lobe tract(mALT)or the medial lateral antennal lobe tract(mlALT)or the lateral antennal lobe tract(lALT).In the mPNs,the dendrites dominate several glomeruli,the somata locate in the lateral cell cluster,the axons project to the higher nervous center via the mALT or the mlALT or the lALT.There are also bilateral PNs in the antennal lobe.In the LNs,there are oligoglomerular LNs and multiglomerular LNs.Among them,almost all of their somata are locate in the LCCL.In the oligoglomerular LNs,the dendrites dominate several glomeruli.But among them,some of their dendrites are thin and sparse,some are rough and dense,some dendrites are rough and dense only in several glomeruli or one glomerulus.In the multiglomerular LNs,the dendrites dominate almost all glomeruli.Among them,some of their dendrites are thin and sparse,some are rough and dense,some LN even appear half dendrites are rough and dense.In the CNs,only two types of them were stained,one with a soma in the central complex,the other one in the contralateral calyx.Except this their morphologies are almost the same,both of their fibers dominate the ipsilateral antennal lobe and the protocerebrum.Except the above,we also stained some unusual morphological neurons.Among them,some with the somata in the antennal lobe,the dendrites dominate glomeruli and the axons project to the gnathal ganglia.Some with the somata in the antennal lobe,the dendrites dominate glomeruli and the axons project to the gnathal ganglia and the protocerebrum.Some with the somata in the LCCL and the axons project to the bilateral calyx and the contralateral antennal lobe.Some of them with somata in one antennal lobe,the dendrites dominate glomeruli and the axons project to the contralateral antennal lobe.Some with the somata in the protecerebrum and the axons project through the antennal lobe with branches,then the axon continue project to the gnathal ganglia and the ventral nerve cord.