Immunoreactive Tracts Research Articles

GABA immunoreactivity in the human cerebellar cortex: a light and electron microscopical study.

The distribution of gamma-aminobutyric acid (GABA) in surgical samples of human cerebellar cortex was studied by light and electron microscope immunocytochemistry using a polyclonal antibody generated in rabbit against GABA coupled to bovine serum albumin with glutaraldehyde. Observations by light microscopy revealed immunostained neuronal bodies and processes as well as axon terminals in all layers of the cerebellar cortex. Perikarya of stellate, basket and Golgi neurons showed evident GABA immunoreactivity. In contrast, perikarya of Purkinje neurons appeared to be negative or weakly positive. Immunoreactive tracts of longitudinally- or obliquely-sectioned neuronal processes and punctate elements, corresponding to axon terminals or cross-sectioned neuronal processes, showed a layer-specific pattern of distribution and were seen on the surface of neuronal bodies, in the neuropil and at microvessel walls. Electron microscope observations mainly focussed on the analysis of GABA-labelled axon terminals and of their relationships with neurons and microvessels. GABA-labelled terminals contained gold particles associated with pleomorphic vesicles and mitochondria and established symmetric synapses with neuronal bodies and dendrites in all cortex layers. GABA-labelled terminals associated with capillaries were seen to contact the perivascular glial processes, basal lamina and endothelial cells and to establish synapses with subendothelial unlabelled axons.

Adipokinetic hormone of the true armyworm, Pseudaletia unipuncta: immunohistochemistry, amino acid analysis, quantification and bioassay

Abstract A cluster of five to seven AKH‐like immunoreactive cells lie in each lobe of the paired corpora cardiaca of the true armyworm, Pseudaletia unipuncta. These cells form a mesh work of immunoreactive processes within the corpora cardiaca, and immunoreactive tracts projecting posteriorly over the aorta.Reversed‐phase high performance liquid chromatography of extracts of the corpora cardiaca of P.unipuncta revealed a single large U.V. absorbent peak with a retention time identical to synthetic Manduca‐AKH. Amino acid analysis of the contents of this peak yielded a composition identical to that of synthetic Manduca‐AKH which was analysed in a parallel manner. Furthermore the material within the peak possessed adipokinetic activity when bioassayed in day 2 adult male P. unipuncta. The corpora cardiaca of similar individuals were found to contain approximately 17.6ng (17.6pmol) of Manduca‐AKH equivalents per pair.Injection of Manduca‐AKH into 2‐day‐old adult male P.unipuncta resulted in a dose‐dependent elevation in haemolymph lipid levels with a maximum level of 80–90μmg/μl obtained with 5–10 ng of Manduca‐AKH. Continuous flight also elevated haemolymph lipid levels in day 4 adult males with a significant elevation evident in the first samples taken after 15 min of flight and lipid levels plateauing at approximately 100 μg/μl by about 60 min of flight.

Glutamate-like immunoreactivity in the cestode Hymenolepis diminuta

Glutamate-like immunoreactivity in the cestode Hymenolepis diminuta was investigated at the light-microscopic level by immunohistochemistry with an antiglutamate antibody. Immunoreactivity was seen in the basal region of the suckers, in the rostellum, subtegumental regions, central nervous system, and longitudinal nerve cords, and in eggs. In the scolex the cerebral ganglia were diffusely immunoreactive, and immunoreactive tracts, passing from the cerebral ganglia to the suckers, were observed. The longitudinal nerve cords contained large groups of intensely stained cell bodies and processes throughout the length of the strobila. Immunoreactive tracts from the longitudinal nerve cords formed junctions with the deep longitudinal muscles only in the lateral regions of the proglottids. However, neuron-like varicose swellings were seen in the subtegumental area of the mature region. The localization of glutamate-like immunoreactivity in various parts of the nervous system and tissues of Hymenolepis diminuta provides further support for the role of glutamate as an excitatory neuromuscular transmitter in the platyhelminths.

Immunohistological demonstration of a substance related to neuropeptide Y and FMRFamide in the cephalic and thoracic nervous systems of the locust Locusta migratoria.

A neuropeptide related to the mammalian neuropeptide Y (NPY) is present in various neurosecretory cells (NSC) of the cephalic and thoracic nervous systems of the insect Locusta migratoria. Immunoreactive perikarya are detected in the protocerebrum, tritocerebrum, optic lobes and the suboesophageal and thoracic ganglia. They give rise to many immunoreactive processes that ramify extensively throughout the neuropiles. In the brain, prominent axon bundles tightly surround the tractus I to the corpora cardiaca. This fiber pattern suggests that the NPY-like substance may have a neuromodulator and/or neurotransmitter function. This substance may also have a neurohormonal role, since some immunoreactive tracts penetrate into neurohaemal organs via the nervi corporis cardiaci II and the thoracic median nerves. NCS containing NPY-like neuropeptide also display an FMRFamide-like immunoreactivity (except for the abdominal part of the metathoracic ganglion). NPY or FMRFamide antisera are not inactivated after preabsorption with FMRFamide or NPY, respectively. It might therefore be inferred that in locust NSC these two antisera recognize two distinct antigenic sites belonging either to a large polypeptide, or to two distinct neuropeptides.