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The immunohistochemical localization of Ca2+/calmodulin-dependent protein kinase type IV (CaM kinase IV) was examined in rat peripheral ganglia and paraganglia as well as brain. In sensory ganglia including the trigeminal and dorsal root ganglia, small- to medium-sized neurons were intensely immunoreactive. In the spinal cord, immunoreactive small neurons were seen in superficial laminae of the dorsal horn, whereas motoneurons were immunonegative. In autonomic ganglia including the superior cervical, celiac, and submandibular ganglia, almost all neurons were intensely immunoreactive for CaM kinase IV. In the small intestine, immunoreactive neurons were seen in the submucosal and myenteric ganglia. In all immunoreactive neurons, the immunoreactivity was localized predominantly in cell nuclei, whereas nucleoli and nerve fibers were completely free from immunoreaction. From the wide distribution and predominant nuclear localization of CaM kinase IV, it is suggested that CaM kinase IV might be involved in the modulation of gene transcription through the nuclear Ca(2+)-signaling in the peripheral as well as central nervous system.

In the present immunohistochemical study the distribution of nitric oxide synthase (NOS) was studied in various autonomic ganglia and in related peripheral tissues of the rat. For comparison some other neuronal markers including acetylcholinesterase and tyrosine hydroxylase as well as several neuropeptides were analysed on adjacent or the same sections. The distribution of NOS-like immunoreactivity (LI) and of these other markers has been semiquantitatively summarized. In some parasympathetic ganglia such as the sphenopalatine and submandibular ganglia NOS-LI was present in most ganglion cells, at least partly coexisting with peptide histidine isoleucine (PHI), vasoactive intestinal polypeptide (VIP) and neuropeptide tyrosine (NPY). In the pelvic ganglia a comparatively smaller proportion of neurons was NOS-positive and they often contained VIP-LI and less frequently NPY-LI. In the tissues innervated by these ganglia, such as nasal mucosa and salivary glands, NOS-positive fibers were observed around blood vessels and within the glandular parenchyma, although generally less abundant than VIP/PHI nerves, while in the uterus, vas deferens and penis a more close correlation was seen. NOS-positive fibers were also widely distributed in other tissues. In the sympathetic ganglia NOS-LI was mainly present in dense fiber networks, which disappeared after transection of the sympathetic trunc central to the ganglion. Since many cell bodies in the sympathetic lateral column of the spinal cord also were NOS-positive, it is likely that the majority of preganglionic fibers innervating sympathetic ganglia are NOS-positive. VIP-positive cells in stellate ganglia did not contain NOS-LI. The present results suggest that NO may be a messenger molecule both in parasympathetic postganglionic neurons and in preganglionic sympathetic neurons.

The immunohistochemical distribution of a recently identified 66-kDa neurofilament protein (NF-66) was investigated in peripheral and autonomic ganglia of the guinea-pig where it has been previously established that other neuronal intermediate filament proteins have a selective distribution. NF-66 immunoreactivity was observed in distinct subpopulations of neurons and did not coexist completely with either the neurofilament triplet or a 57-kDa intermediate filament protein (peripherin). NF-66 labelling was identical to that observed with an antibody to a 150-kDa intermediate filament or associated protein (CH1). These results further demonstrate that different neuronal intermediate filament proteins are present in selective subpopulations of neurons and that these proteins are, therefore, likely to have cell type-specific roles.

Diabetic autonomic neuropathy results in significant morbidity and mortality. Both diabetic humans and experimental animals show neuroaxonal dystrophy of autonomic nerve terminals, particularly in the prevertebral superior mesenteric ganglia (SMG) and celiac ganglia (CG) which innervate the hyperplastic/hypertrophic diabetic small intestine. Previously, investigators suggested that disturbances in ganglionic nerve growth factor (NGF) content or transport might play a pathogenetic role in diabetic autonomic pathology. To test this hypothesis, we measured NGF content and NGF receptor expression, p75(NTR) (low affinity neurotrophin receptor) and trkA (high affinity NGF receptor), in control and diabetic rat SMG, CG and superior cervical ganglia (SCG). Surprisingly, rather than a decrease, we observed an approximate doubling of NGF content in the diabetic SMG and CG, a result which reflects increased NGF content in the hyperplastic diabetic alimentary tract. No change in NGF content was detected in the diabetic SCG which is relatively spared in experimental diabetic autonomic neuropathy. NGF receptor expression was not consistently altered in any of the autonomic ganglia. These observations suggest that increased NGF content in sympathetic ganglia innervating the diabetic alimentary tract coupled with intact receptor expression may produce aberrant axonal sprouting and neuroaxonal dystrophy.

Prevertebral sympathetic ganglia develop markedly enlarged argyrophilic neurites as a function of age, gender and diabetes. Immunolocalization studies demonstrate their preferential labeling with antisera to highly phosphorylated 200 kDa neurofilament (NF-H) epitopes, NPY, peripherin and synapsin I, but not to hypophosphorylated NF-M and NF-H or MAP-2. The immunophenotype of dystrophic neurites in conjunction with the results of histochemical and ultrastructural studies are consistent with the terminal axonal and/or synaptic origin of neuritic dystrophy in the sympathetic ganglia of aged and diabetic human subjects.

NADPH-diaphorase histochemistry, which identifies neural sites of nitric oxide production, demonstrated intensely stained nerve terminals surrounding the cell bodies of a subpopulation of neurons in rat prevertebral celiac and superior mesenteric sympathetic ganglia but failed to comparably label terminals in paravertebral superior cervical ganglia or perikarya in any sympathetic ganglion. The superior mesenteric ganglia of aged and diabetic rats, in which synaptic dysplasia (neuroaxonal dystrophy) is prominent, failed to show involvement of diaphorase containing nerve terminals.

A slow, 4-aminopyridine-sensitive K+ current was observed inRana pipiens autonomic neurones when they were studied under whole-cell patch-clamp recording conditions. This ‘slow-A’ current (ISA), which was independent of extracellular Ca2+, exhibited a similar voltage dependence to a classical A current (IA) yet inactivated with an 80-fold slower time course. AlthoughISA is difficult to distinguish from the delayed rectifier K+ current (IK), muscarine enhanced the current in sympathetic neurones and either enhanced or suppressed the current in parasympathetic neurones. Effects on slow transient outward currents must therefore be considered when attempting to understand cholinergic modulation of repetitive discharge in autonomic neurones.

The purpose of this study was to determine whether the blood vessels of transplanted neural tissue retain their functional characteristics. Quantitative autoradiography was used to measure local blood flow (F) with iodoantipyrine and the blood-to-tissue transfer constant (K) with alpha-aminoisobutyric acid in superior cervical ganglion (SCG) allografted to the surface of ventricle IV and into the cerebellum of the same rat. The F of the intraparenchymal grafts was slightly lower than that of the intraventricular grafts; F decreased between 1 and 4 weeks in SCG grafts at both sites. The permeability-surface area (PS) product of the microvessels and extraction fraction of AIB were calculated from these results and indicated restricted transvascular passage of the amino acid in both the in situ and grafted SCG. Surface area (S) and average length (L) of the microvessels were determined morphometrically and their permeability (P) was calculated from these data. Although K and PS decreased in the grafts compared to in situ SCG, a comparable decrease in S indicated that P was similar for the microvessels of both in situ and 1-week-old SCG transplants: 3.5-4.3 x 10(-6) cm/s. Between 1 and 4 weeks after transplantation, the P of the microvessels decreased to approximately 1.6-2.3 x 10(-6) cm/s without any change in S. Thus, the blood vessels of SCG grafts within or upon the brain initially retain the functional attributes of in situ SCG microvessels, but the average permeability of the graft microvessels decreases to approximately one half of the initial value by 4 weeks after transplantation.

We have previously shown that certain commercially available lots of alpha-bungarotoxin block transmission in ciliary and choroid neurons of both pigeon and chicken ciliary ganglia at a concentration of 10 microgram/ml (1.2 microM). The blockade is antagonized by pre-incubation with 100 microM tubocurarine. Further evidence that this blockade is produced by a postsynaptic action, as one would expect of an alpha-neurotoxin, are our findings that: (a) exposure to the toxin prevents the depolarization of ganglion cells normally seen in response to the cholinergic agonist, carbachol; and (b) the blocking activity of the toxin is removed by treatment with membranes purified from Torpedo electric organ containing an excess of alpha-neurotoxin binding sites. A high affinity binding site for [125I]alpha-bungarotoxin was characterized in the chicken ciliary ganglion. However, since it is labelled equally well by lots of alpha-bungarotoxin which block transmission and those that do not, this site does not appear to be involved in the blockade of transmission. alpha-Cobratoxin (from Naja naja siamensis), the alpha-neurotoxin L.s. III (from Laticauda semifasciata) and certain lots of alpha-bungarotoxin produce a partial blockade of transmission in ciliary neurons of the pigeon ciliary ganglion at a concentration of 10 microgram/ml (1.2 microM), but have no effect on transmission in choroid neurons. Two other alpha-neurotoxins from Laticauda semifasciata, erabutoxin a and erabutoxin b, have no effect on transmission in either cell population at this concentration. None of the alpha-neurotoxins tested had any effect on transmission in either the rat superior cervical ganglion or the rat pelvic ganglion at concentrations up to 100 microgram/ml (12 microM). Collagenase treatment of these ganglia, in an attempt to increase access of the toxins to ganglion cells, did not alter these negative results. beta-Bungarotoxin (0.5 microgram/ml, 0.02 microM) produces a complex blockade of transmission in both avian ciliary ganglia and rat superior cervical ganglia. Unlike the action of alpha-bungarotoxin, the blockade of ciliary ganglion transmission by beta-bungarotoxin is irreversible and is not prevented by pretreatment with tubocurarine.

In a preliminary study a difference in the uptake and transport of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) between the trigeminal ganglion and the superior cervical ganglion was observed. After injection of WGA-HRP and HRP into the trigeminal ganglion, peroxidase was found in the space between the satellite cell processes and the ganglion cells. The ganglion cells showed pinocytosis and uptake of WGA-HRP and HRP. In the superior cervical ganglion WGA-HRP and HRP were found alongside the satellite cells but were absent in the space between satellite cells and ganglion cells. Intravenous injection revealed the presence of HRP in the space between sensory ganglion cells and their satellite cells of the trigeminal and nodose ganglion whereas HRP was absent in the space between autonomic ganglion cells and their satellite cells of the superior cervical, medial cervical and pterygopalatine ganglion although HRP lined the satellite cell membranes. By means of electron microscopy, satellite cell processes in the superior cervical ganglion were found to enwrap ganglion cells very tightly with a marginal space between both cell types. Satellite cells and their proceses were mutually anchored by numerous tight junctions. In the trigeminal ganglion the extracellular space between ganglion cells and satellite cells was larger and satellite cells were found to be more loosely arranged around the ganglion cells. Satellite cell processes were only occasionally linked by tight junctions. It is concluded that satellite cells in autonomic ganglia comprise an effective barrier for WGA-HRP and HRP and probably large molecules in general. This barrier is absent in sensory ganglia.

It is not known whether cranial and spinal ganglia contain autonomic (motor) neurons in addition to sensory cells. Early light microscopic studies indicate the possibility of synaptic input to some nerve cells via perisomatic axon terminals and dendrites. It has also been suggested that visceromotor relay-type cells in the petrosal ganglion might be involved in the efferent control of the carotid body. The present ultrastructural analysis of 902 neurons in 17 levels from two cat petrosal ganglia provides no evidence for synapses on the cell somata or on their axonal extensions. Processes resembling dendrites were lacking although small surface projections typical of sensory cells were common. The petrosal ganglion thus appears to consist entirely of afferent unipolar neurons.

Autonomic ganglia have a population of small intensely fluorescent (SIF) cells with unknown function. We have investigated the afferent innervation of SIF cells in bullfrog sympathetic ganglia using intracellular recordings and light microscopy of stained preganglionic axon terminals. Contrary to previous knowledge, bullfrog SIF cells do indeed receive functional synaptic input and this innervation is provided solely by the C-type preganglionic nerve fibers.

Autonomic (superior cervical) ganglia area grafted either into the IV ventricle where minimal trauma occurred or directly into the cerebral cortex which was necessarily traumatic. Previous studies have shown that host astroglia may migrate into autonomic tissue grafts. The purpose of the present study was to compare and contrast the astroglial response in allo- and autografts. By monitoring the host response in the two model sites using glial fiobrillary acidic protein (GFAP) immunostaining in 1 μm plastic sections we sought to determine the role of injury stimulus in astroglial migration. In addition, these models could be used to investigate any potential differences in glial reactivity produced by allo- or autograft antigenic stimulation. In both ventricular and parenchymal locations, astroglia migrated progressively into allografts. Migration, which could have taken place along anastomotic vascular connections, began after one week and was continual, eventually replacing graft neural tissue. Astrocytic processes appeared enlarged and highly immunoreactive only as they entered the allografts or were in close association with the choroid plexus; adjacent host astrocytes were unaltered. Glial migration was greatly reduced in ventricular autografts but in the parenchymal site was nearly comparable to that of allografts. It was suggested that certain immunological factors may be involved in glial reactivity or migration considering the observed differences in the non-traumatic model whereas tissue damage stimulus played a major role in migration in both allo- and autografts. In no instances were typical astrocytic end-feet found on the autonomic graft vessels. The host astrocytic response to grafted autonomic tissue occurred significantly later (5–7 days) than the host endothelial response. This observation indicates that the graft vessels were original, intrinsic ones and the astrocytic invasion played no role in influencing endothelium with regards to brain-barrier properties.

Bungarotoxin was shown to inhibit the synaptic transmission in the rat superior cervical ganglion. As the inhibition proved to be reversible, just as in avian autonomic ganglia, it is assumed that the ganglionic acetylcholine receptors reacting with bungarotoxin are different from those of skeletal muscle or electric organ.

The effect of substance P on presynaptic nerve terminals was examined by intracellular impalements of calyciform terminals within the chick ciliary ganglion. Substance P produced a slow depolarization of the nerve terminals which was associated with an increase in input resistance. The postsynaptic ciliary neurons were unaffected by exposure to substance P, indicating that at this synapse the physiological effects of substance P may be largely presynaptic in nature.