Localization of the two protein kinase C beta-mRNA subtypes in cat visual system.

Protein kinase C (PKC) consists of a family of different subtypes encoded by different PKC genes. We investigated the distribution of PKC beta 1 and PKC beta 2 in the visual system of the adult cat by in situ hybridization using oligonucleotide probes complementary to the PKC beta 1 and PKC beta 2 mRNAs, two splicing variants of the same gene transcript. In the primary visual cortex PKC beta 1 and PKC beta 2 were both present. The laminar distribution patterns found for the two PKC subtypes were identical. A remarkable finding was the difference between the laminar distribution of the PKC beta s in areas 17 and 18 when compared with area 19. In all three areas the highest expression levels were found in layer VI, moderately high levels were found in layers II, III and V, while layer I was devoid of signal. In area 17 and 18 layer IV stood out by its low PKC beta signal. In sharp contrast, layer IV of area 19 was indiscernible from the superficial layers because of an evenly high signal. In the dLGN of the adult cat PKC beta 1 and PKC beta 2 mRNAs were distributed rather homogeneously over the different layers, but the expression levels for PKC beta 1 were clearly higher than those for PKC beta 2.

Histochemical changes of substance P, FRAP, serotonin and succinic dehydrogenase in the spinal cord of rats with adjuvant arthritis.

Various histochemical changes were found in spinal segments L4-L5 of rats with adjuvant arthritis, predominantly 30 days after inoculation. A slight to marked increase of substance P immunoreactivity occurred in laminae I, II and X. FRAP activity was enhanced in lamina II. Serotonin immunoreactivity was heavier in laminae I, VIII and IX in a few animals. The intensity of the histoenzymological reaction for succinic dehydrogenase increased in certain laminae VIII and X neurons. At day 15 of the disease the increase of substance P and FRAP activities was chiefly restricted to the medial portion of the superficial dorsal horn. There was a significant positive correlation between the scratching behaviour of arthritic rats and the substance P immunoreactivity in laminae X and I. If one accepts that scratching is pain-related, the data are consistent with a possible role of substance P in the chronic pain associated with adjuvant arthritis. They leave undetermined the significance of the other histochemical changes.

Cholecystokinin neuron systems and their interactions with the presynaptic features of the dopamine neuron systems. A morphometric and neurochemical analysis involving studies on the action of cholecystokinin-8 and cholecystokinin-58.

A unique role for CCK-58 compared to that for CCK-8 has been demonstrated in the modulation of central catecholaminergic mechanisms and neuroendocrine functions. It is of paramount importance to localize CCK-58 immunoreactivity within the brain in order to establish if separate CCK-58- and CCK-8-immunoreactive neuron systems exist. The two most significant actions of CCK-58 are a marked lowering of TSH secretion and a selective increase of DA turnover in DA-CCK co-existing synapses in the nucleus accumbens and tuberculum olfactorium.

Co-existence of cholecystokinin- or gastrin-like peptides with other peptides in the hypophysis and the hypothalamus.

The presence of cholecystokinin and gastrin has been reported in the hypothalamohypophyseal system. These peptides present a peculiar distribution in the hypothalamic nuclei, the median eminence, and the neurohypophysis. CCK and gastrin have close relationships with other peptides like oxytocin, CRF, vasopressin, and the enkephalins; these relationships vary in different projecting areas and in different types of hypothalamic neurons. The functional role of G-CCK in neurosecretion seems to be linked to the role of these closely associated peptides and certainly deserves further investigation.

Processing of proenkephalin is tissue-specific.

Most neuropeptides are synthesized as large precursor proteins. These precursors undergo a maturation process involving several proteolytic events that generate the biologically active peptides. The enzymatic mechanisms underlying this processing are still largely unknown. The processing of the precursor protein proenkephalin was studied in two different bovine tissues, the hypothalamus and adrenal medulla. The high molecular weight enkephalin-containing peptides that accumulate in these two tissues were found to be different, indicating the existence of two processing pathways for this neuropeptide precursor.

Proenkephalin, [Met]enkephalin, and oxytocin immunoreactivities are colocalized in bovine hypothalamic magnocellular neurons.

The distribution of proenkephalin and [Met]enkephalin immunoreactivities in the bovine hypothalamo-neurohypophyseal system was studied by use of specific antisera. Proenkephalin and [Met]enkephalin immunoreactivities were found in magnocellular neuronal cell bodies in the dorsal part of the supraoptic nuclei and in the peripheral part of the paraventricular nuclei. A densely staining network of nerve terminals was found in the external part of the median eminence and in the posterior hypophysis. This general distribution is identical to that of the neurohypophyseal hormone oxytocin. The precise localization of proenkephalin and [Met]enkephalin immunoreactivities was compared to the distribution of oxytocin and vasopressin in serial 5-micron sections through the magnocellular nuclei. Oxytocin immunoreactivity was nearly always present in cells that were stained with proenkephalin and [Met]enkephalin antisera. The vasopressin-immunoreactive cells were never stained with either the proenkephalin or the [Met]enkephalin antisera.

Coexistence of cholecystokinin and oxytocin-neurophysin in some magnocellular hypothalamo-hypophyseal neurons.

The existence of cholecystokinin in the posterior hypophysis and its hypothalamic origin have been unequivocally demonstrated. Immunocytochemical evidence is presented for the coexistence of gastrin-cholecystokinin and oxytocin-neurophysin I immunoreactivities in some magnocellular neurons of the supraoptic and paraventricular nuclei both in rat and bovine hypothalamus.

Immunohistochemical localization of cholecystokinin- and gastrin-like peptides in the brain and hypophysis of the rat.

The distribution of gastrin-cholecystokinin-like peptide(s) is reported in brain and hypophysis of the rat. The unlabeled peroxidase-antiperoxidase complex immunohistochemical technique was used. Controls of specificity for various peptides were studied with solid-phase absorption. Colchicine treatment was necessary to obtain positivity in many neuronal cell bodies. In addition to their already known distribution, gastrin-cholecystokinins containing neural cell bodies and fibers were present in olfactory structures, in various preoptic and hypothalamic nuclei (except in mamillary bodies), in mesencephalic nucleus linearis rostralis, and in A-10, A-9, and A-8 regions of Dahlström and Fuxe, which include substantia nigra. From previous investigations and the present distribution study, it can be inferred that, although most of the brain material consists of cholecystokinin, gastrins may also be present in hypothalamo-posthypophyseal magnocellular cells, in nucleus tractus solitarii, and in the dorsal horn of the spinal cord. The distribution of positive cell bodies in the peripheral part of the paraventricular nucleus and in the dorsal part of the supraoptic nuclei in the hypothalamus is similar to that of oxytocin neurons. The localization of positive cell bodies in A-10, A-9, and A-8 regions of Dahlström and Fuxe is similar to that of dopaminergic neurons. The mesencephalic concentration of cell bodies and the wide distribution of fibers in striatal, hypothalamic, septal, and other hemispheric structures together with thick positive fibers in the medial forebrain bundle is consistent with the existence of ascending mesencephalic pathways, including the nigrostriate pathway.