Octopamine immunoreactive neurons in the fused central nervous system of spiders

• Published in: Brain research Vol. 611; no. 2; pp. 197 - 206
• Main Authors: Seyfarth, Ernst-August, Hammer, Klaus, Spörhase-Eichmann, Ulrike, Hörner, Michael, Vullings, Henk G.B.
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 21.05.1993; Amsterdam Elsevier; New York, NY
• Subjects: Animals; Arachnida; Arthropods - anatomy & histology; Biochemistry. Physiology. Immunology; Biological and medical sciences; Cupiennius salei; Female; Fundamental and applied biological sciences. Psychology; Ganglia - anatomy & histology; Ganglia - cytology; Hemolymph; High-pressure liquid chromatography; Immunocytochemistry; Immunohistochemistry; Invertebrates; Nervous System - anatomy & histology; Nervous System - cytology; Neuroanatomy; Neurons - cytology; Octopamine; Octopamine - analysis; Physiology. Development; Species Specificity; Spider nervous system; Spiders - anatomy & histology; Spider nervous system; Immunocytochemistry; Octopamine; Neuroanatomy; Cupiennius salei; High-pressure liquid chromatography; Hemolymph; Hormone; Immunohistochemistry; HPLC chromatography; Nervous system; Projection; Anatomy; Arachnida; Neuron; Neuromodulator; Suboesophageal ganglion; Arthropoda; Neuromediator; Biogenic amine; Invertebrata
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/0006-8993(93)90503-F

Using antisera directed against octopamine (OA), we identified and mapped octopamine-immunoreactive (OA-ir) neurons and their projections in the fused, central ganglion complex of wandering spiders, Cupiennius salei. Labeled cell bodies are concentrated in the subesophageal ganglion complex (SEG) where they are arranged serially in ventral, midline clusters. OA-ir processes from these cells project dorsally. Some neurites end close to segmental septa; others merge into longitudinal tracts connecting the neuromeres. Labeled collaterals leaving these tracts project into peripheral neuropil. In the brain, OA-ir somata were found only in the two cheliceral hemiganglia, where a cluster of 4–5 relatively large cells (soma diameter 25 μm) lies next to a group of small somata (diameter < 10 μm). Neurites originating from the large somata descend int the SEG and merge into longitudinal tracts. The central body of the brain contains profuse ascending projections. Except for fine varicosities that are confined to the roots of nerves, we found no OA-ir fibers leaving the central nervous system (CNS). Within the CNS, however, OA-ir varicosities are concentrated in neuropil and near hemolymph spaces. This distribution suggests that OA acts as a neurotransmitter and/or local neuromodulator at central synapses, while it is also released into the hemolymph and presumably acts hormonally at peripheral sites. Using high-pressure liquid chromatography measurements, the hemolymph was in fact found to contain 12–40 nM of free octopamine.