Immunocytochemical localization of GAD isoforms in the CNS ganglia of the cobweb spider, Achaearanea tepidariorum

Immunocytochemical localization of GAD isoforms in the CNS ganglia of the cobweb spider, Achaearanea tepidariorum

Glutamic acid decarboxylase (GAD) is an enzyme that catalyzes the decarboxylation of glutamate to γ‐aminobutyric acid (GABA) and CO2. It has been discovered that the GAD has a restricted tissue distribution and it is highly expressed in the cytoplasm of GABAergic neurons in the CNS where GABA is used as a neurotransmitter. We have examined the microstructure of ganglionic neurons and nerves arising from the CNS and describe here the immunocytochemical localization of GAD isoforms to reveal the ecophysiological significance of GABA for the web‐building spider"s behavior. In the CNS of the cobweb spider, Achaearanea tepidariorum, immunocytochemical localization of GAD isoforms can be detected in the neurons and neuropiles of the optic lobes. In addition, GAD‐like immunoreactive cell bodies are observed at the intrinsic cell bodies near the central body and the symmetric cell clusters of the protocerebrum. However, the fibrous masses within the protocerebral ganglion are not labeled at all. Based on its interconnection with other regions of the CNS, our findings suggest that the central body in the web‐building spider may act as an association center as well as a visual center.

Glutamic acid decarboxylase (GAD) is an enzyme that catalyzes the decarboxylation of glutamate to γ‐aminobutyric acid (GABA) and CO2. It has been discovered that the GAD has a restricted tissue distribution and it is highly expressed in the cytoplasm of GABAergic neurons in the CNS where GABA is used as a neurotransmitter. We have examined the microstructure of ganglionic neurons and nerves arising from the CNS and describe here the immunocytochemical localization of GAD isoforms to reveal the ecophysiological significance of GABA for the web‐building spider"s behavior. In the CNS of the cobweb spider, Achaearanea tepidariorum, immunocytochemical localization of GAD isoforms can be detected in the neurons and neuropiles of the optic lobes. In addition, GAD‐like immunoreactive cell bodies are observed at the intrinsic cell bodies near the central body and the symmetric cell clusters of the protocerebrum. However, the fibrous masses within the protocerebral ganglion are not labeled at all. Based on its interconnection with other regions of the CNS, our findings suggest that the central body in the web‐building spider may act as an association center as well as a visual center.