Distribution of corticotropin-releasing factor in the cerebellum and precerebellar nuclei of the cat.

The present study analyzes the distribution of corticotropin-releasing factor-immunoreactive (CRF-IR) fibers and neuronal cell bodies within the cerebellum and brainstem, respectively, of the cat. Within the cerebellum, CRF is present in climbing fibers, mossy fibers, and a population of varicose fibers which traverses the lower molecular layer. CRF-IR fibers are present throughout all lobules of the cat cerebellar cortex, though the density and immunostaining intensity of each fiber system vary. Bands of intensely immunoreactive climbing fibers are prominent within the vermis, intermediate cortex, and crus II. Bands of intensely immunoreactive mossy fiber terminals accompany the climbing fiber bands within the vermis. Collaterals of climbing and mossy fibers contribute to a beaded fiber plexus localized to the Purkinje cell layer. Varicose fibers containing CRF immunoreactivity are present in all deep cerebellar nuclei. CRF-IR neuronal cell bodies are prominent within several brainstem nuclei known to project to the cerebellum: all divisions of the inferior olivary complex, the lateral reticular nucleus, paramedian reticular nucleus, gigantocellular reticular nucleus, raphe nuclei, perihypoglossal complex, medial and inferior vestibular nuclei and cell groups f and x, locus ceruleus, and nucleus subceruleus. This study confirms and extends a previous study of CRF distribution within cerebellar afferent systems of the cat (Cummings et al.: J. Neurosci. 8:543-554, '88) and compares this distribution with previous descriptions in other species. The ubiquitous distribution of CRF throughout the cat cerebellum suggests a primary role for this peptide in signal transduction.

Early development of cerebellar afferent systems that contain corticotropin-releasing factor.

Corticotropin-releasing factor (CRF) and CRF binding sites have been described in the cerebellum of several species, including the North American opossum (Didelphis marsupialis virginiana), the species used in the present study. Inotophoretic application of this peptide in the adult cerebellum enhances the spontaneous and amino acid-induced firing rate of Purkinje cells and overcomes the GABA-induced suppression of Purkinje cell activity. The present account provides immunohistochemical evidence for the localization of CRF in the North American opossum within developing axons and their growth cones prior to the formation of the Purkinje cell and granule cell layers. CRF mRNA is present on postnatal day (PD) 1 within the internal migratory stream of the ventral lateral medulla, which contains migrating olivary neurons, and within the ventral medulla in the region, where inferior olivary neurons first aggregate to form the inferior olivary complex. The olivary complex can first be identified on PD2 and is well defined by PD3. CRF-immunoreactive axons are evident within the cerebellar primordium on PD4 and penetrate the nascent Purkinje cell layer between PD14 and PD26. By PD26, CRF-immunoreactive puncta are organized within the Purkinje cell layer as parasagittal bands. Thus, olivary neurons express CRF mRNA prior to the time that the first CRF-labeled axons are present in the cerebellar anlage (PD4), suggesting that olivary axons are among the first to reach the developing cerebellum. Coincident (PD1-3) with the early transcription of CRF mRNA in the inferior olive, cells in the medullary reticular formation (PD1) and locus coeruleus (PD2) also transcribe CRF mRNA. These brainstem sites also could provide CRF-immunoreactive axons to the developing cerebellum; however, based on the results of this study and correlative data reported in the literature, we propose that the primary source of early-arriving CRF fibers is the inferior olivary complex. The early arrival of CRF-containing axons in the cerebellum prior to synaptogenesis and migration of both granule cells and Purkinje cells suggests a role for this peptide in target recognition and synaptic organization.

Distribution of corticotropin-releasing factor in the cerebellum and precerebellar nuclei of the opossum: a study utilizing immunohistochemistry, in situ hybridization histochemistry, and receptor autoradiography.

This study reports 1) a nonhomogeneous distribution of three morphologically distinct, corticotropin-releasing factor (CRF)-immunoreactive axonal phenotypes within the cerebellum of the opossum: climbing fibers, mossy fibers, and beaded fibers within the ganglionic plexus; 2) the existence of CRF binding sites within the cerebellar cortex; and 3) the distribution of CRF-containing neurons in brainstem precerebellar nuclei identified with immunohistochemistry and in situ hybridization histochemistry. CRF-immunoreactive climbing and/or mossy fibers were identified within all cerebellar lobules. The density of CRF-immunoreactive fibers was greatest in the vermis, where longitudinal bands of intensely immunoreactive climbing and mossy fibers were interspersed with regions containing fibers demonstrating lower levels of immunolabeling. CRF-immunoreactive fibers were present within all deep cerebellar nuclei. The topography of CRF-containing cerebellar fibers is discussed with respect to possible sites of origin within the brainstem. CRF-immunoreactive neurons were identified in all nuclei of the inferior olivary complex, although the number and intensity of immunostaining of CRF-containing cells varied within and among individual nuclei. CRF-immunoreactive somata were also present in brainstem nuclei known to give rise to cerebellar mossy fibers. In situ hybridization histochemistry utilizing an 35S-labeled synthetic 48-base oligodeoxynucleotide complementary to amino acids 22-37 of rat CRF proper revealed that CRF mRNA is transcribed in precerebellar nuclei. Variation in the level of CRF mRNA was detected among inferior olivary nuclei, in correspondence with variations detected in the levels of immunostaining. Data from this study suggest that variation in the level of CRF immunoreactivity detected within cerebellar afferent fibers may correlate with the level of CRF mRNA within cell bodies of origin of the projections. In vitro receptor autoradiography, utilizing 125I-Tyro-ovine CRF, revealed correspondence between CRF binding sites and CRF-immunoreactive fibers in the cerebellar cortex. Results of this study support suggestions for CRF-mediated circuitry in the cerebellum.

Temporal-spatial pattern of c-Fos expression in the rat brain in response to indispensable amino acid deficiency. II. The learned taste aversion.

Rats rapidly become anorectic when eating an amino acid-imbalanced diet that induces a deficiency of an indispensable amino acid. Recognition of amino acid deficiency is thought to be a function of the anterior piriform cortex. However, the neuronal circuitry underlying the secondary learned aversion to such diets may involve the amygdala. In this study, Fos immunohistochemistry was employed to identify regions of the brain activated during the learned aversion phase of the response to an amino acid-imbalanced diet. c-Fos expression was examined in the brains of rats at intervals from 1 to 6 h after introduction of a diet imbalanced in threonine, a corrected (amino acid-balanced) diet or a basal (low protein) diet. The study has revealed that, within the time frame associated with the learned aversive response, Fos-immunoreactive (Fos-IR) neurons increased selectively in the central nucleus of the amygdala in animals fed a threonine-imbalanced diet. These results suggest a temporal relationship between changes in neuronal activity in the central nucleus of the amygdala and the learned aversion associated with acute amino acid deficiency.

Temporal-spatial pattern of c-fos expression in the rat brain in response to indispensable amino acid deficiency. I. The initial recognition phase.

Rats reduce their food intake after ingestion of a small amount of an amino acid imbalanced (AA-IMB) diet that induces a pronounced amino acid deficiency. Two hours after ingesting a threonine-IMB diet, just when food intake is depressed significantly, the concentration of threonine is decreased in some but not all brain areas. Neural recognition of this decrease in the limiting amino acid is thought to be the first step in the anorectic responses to AA-IMB diets. To identify the regions of the brain that may be activated upon recognition of an AA-IMB diet, we examined the temporal-spatial distribution of Fos immunoreactive neurons at intervals after introduction of either threonine-IMB or control diets. We found that Fos immunoreactivity in the anterior piriform cortex and immediately surrounding areas, along with the infralimbic cortex, was increased selectively early (by 2 h) after introduction of the AA-IMB diet, and remained elevated through 3 h. The anterior piriform cortex is believed to function in neural recognition of amino acid deficiency. Fos immunoreactivity in the AA-IMB group increased over the control diet groups somewhat later in the dorsomedial nucleus of the hypothalamus. We hypothesize that these areas in the rostral forebrain may serve as neural relays in the early phases of the anorectic responses that occur upon recognition of amino acid deficiency.

Harmaline-induced changes in gamma aminobutyric acid(A) receptor subunit mRNA expression in murine olivocerebellar nuclei.

Increased CNS activity in the form of electrically or chemically induced seizures is known to alter the properties of GABA(A) receptors. The tremorgen, harmaline, causes a bursting pattern of activity in inferior olivary neurons, the effects of which are transmitted throughout the olivocerebellar circuit to other regions of the CNS. In situ hybridization was used to determine the effect of this increased activity on gamma aminobutyric acid(A) (GABA(A)) receptor subunit gene expression in the cerebellar Purkinje cell layer, deep cerebellar nuclei and inferior olivary complex of adult mice. In Purkinje cells, the expression of alpha(1), beta(2), and gamma(2) mRNAs was increased only slightly (<5%) by harmaline administration, while in deep cerebellar neurons, beta(2) transcript levels were initially elevated (26%), but dropped to control levels immediately thereafter. The expression of alpha(2), alpha(4), beta(3) and gamma(1) mRNAs in olivary neurons was affected differentially by harmaline administration. The alpha(4) transcript was increased, reaching >60% above control levels at 6 h post-injection. A smaller increase was observed for alpha(2) mRNA, while beta(3) and gamma(1) transcripts dropped below control levels during the same period. The expression of corticotropin-releasing factor mRNA was also elevated in the olivary complex. These data indicate that while Purkinje cells and deep cerebellar neurons are only minimally affected, harmaline induced changes in cellular properties may result in increased numbers of alpha(4)-containing, diazepam-insensitive, GABA(A) receptors in olivary neurons.

Neuropeptide Y and somatostatin in the anterior piriform cortex alter intake of amino acid-deficient diets.

Neuropeptides affect food intake via peripheral and brainstem mechanisms, but their roles in mediating feeding via the cerebral cortex have received little attention. The anterior piriform cortex (APC) appears to play a critical role in neuroperception of deficiencies of essential amino acids (AA) and the anorectic response to such deficiencies. The neural circuitry underlying the role of this paleocortex in these events is not understood. We have shown that neurons containing neuropeptide Y (NPY) and somatostatin (SOM) are cytoarchitecturally in positions to relate synaptically to the neurons of the APC which may mediate responses to AA. Thus, we hypothesized that NPY and SOM administered intracortically to the APC would directly affect food intake in a threonine-imbalanced model. We determined that NPY at 1-1.5 nmol decreased intake of the AA-deficient diet for 3 h, with a cumulative effect that extended through 6 h. SOM had a dual effect; at 1 pmol it increased intake of the AA-deficient diet for 3 h; at 2 nmol, SOM decreased intake of the AA-deficient diet for over 9 h, with a cumulative effect that persisted through 12 h. In the first 3 h, intake of animals receiving 1 pmol of SOM differed significantly from those receiving 2 nmol. These results suggest that NPY and SOM affect the cortical circuitry responsible for recognition of deficiencies in nutritionally essential AA, and that the timing of the cortical responses to the peptides may be related to the time course of the anorectic responses.

Luque trolley and convex epiphysiodesis in the management of infantile and juvenile idiopathic scoliosis.

STUDY DESIGN: Retrospective analysis of 5-year follow-up data from patients instrumented with Luque trolley with or without convex epiphysiodesis for management of progressive infantile and juvenile idiopathic scoliosis. OBJECTIVE: To assess results, establish predictors of outcome, and suggest more effective surgical interventions. SUMMARY OF BACKGROUND DATA: Initial results have been reported. There are no long-term follow-up studies. METHODS: Luque trolley instrumentation was used in eight patients with idiopathic scoliosis between 1983 and 1984. Luque trolley with convex epiphysiodesis was used in 18 patients between 1984 and 1990. RESULTS: Changes in Cobb angle from 8-week to 5-year follow-up are as follows. For Luque trolley alone, Cobb angle worsened for all patients. For progressive infantile scoliosis managed with Luque trolley and convex epiphysiodesis, Cobb angle worsened in seven, remained unchanged in four, and improved in two patients. Mean age at operation was 3.1 years (range, 1.5-7.4 years), and instrumented spinal growth was 32% of expected growth. Preoperation Cobb angle was 65 degrees (range, 40-95 degrees). Cobb angle at 5-year follow-up was 32 degrees (range, 0-86 degrees), which is predicted by preoperation apical concave rib-spinal angle (P = 0.002) and upper end vertebral tilt (P = 0.04). For juvenile idiopathic scoliosis managed with Luque trolley and convex epiphysiodesis, Cobb angle worsened in three patients and improved in one. CONCLUSIONS: Luque trolley instrumentation alone does not prevent curve progression. Additional convex epiphysiodesis results in curve resolution in some patients, which suggests a growth effect. Both spine and rib factors predict Cobb angle at 5-year follow-up.

Neuropeptide Y, somatostatin, and cholecystokinin of the anterior piriform cortex.

In addition to its role in olfaction and as a primary epileptogenic site, the anterior piriform cortex has been suggested to play a role in neuroperception of deficiencies or imbalances in physiologically essential amino acids. In recent studies, amino acid deficient diets were shown to induce expression of c-fos in the anterior piriform cortex within the rapid time frame associated with the normal anorectic response to such diets. It became important to examine the neurocytochemical architecture of this region for clues as to how and more precisely where dietary amino acid deficiency or imbalance might be monitored. The relationships of neuropeptide Y-, somatostatin-, and cholecystokinin-containing neurons were of particular interest because ongoing studies indicate that those peptides administered to the anterior piriform cortex alter intake of diets deficient in essential amino acids. The neuropeptides were endogenous to intrinsic neurons only; none resembled pyramidal projection neurons. Peptidergic neurons and fibers were concentrated most heavily in layer III of the paleocortex. The cytoarchitecture suggests that neuropeptide Y-, somatostatin-, and cholecystokin-containing neurons of the anterior piriform cortex may relate synaptically or multisynaptically to local circuit neurons during electrical activity, modulation of olfactory information, and neuroperception of essential amino acids.

Accuracy of references in four pediatric nursing journals.

Inaccurate references hinder retrieval of documents, may prevent researchers from examining all of the work by an author, and may result in authors not getting credit for their work. This study determines the number and types of errors in references in four widely read pediatric nursing journals. Of the 190 references examined, 79 of them contained an error, for an overall error rate of 41.6%. Major errors, which prevent the rapid retrieval of information, occurred in 28.9% of the references. Minor errors occurred at half the rate (13.7%) of major errors. Errors in the titles of articles, chapters, and books were the most common type of mistake followed by errors in authors' names.

Anorectic responses to dietary amino acid imbalance: effects of vagotomy and tropisetron.

We investigated the roles of the vagus nerve and the serotonin3 (5-HT3) receptor in mediating the food intake depression associated with amino acid deficiency. The food intake of sham-operated (sham) rats given an isoleucine-imbalanced (IMB) diet was reduced to < 40% of control basal (BAS) diet intake (P = 0.0009), and pretreatment with the 5-HT3 antagonist tropisetron (Trop) increased IMB intake by twofold over the vehicle (VEH)-treated group (P < or = 0.0001), as we have reported before. However, after subdiaphragmatic vagotomy (VAGX), IMB intake was increased to a level intermediate between the sham-VEH and sham-Trop groups, while administration of Trop did not increase IMB intake over VAGX alone. By the end of day 1, the VAGX-Trop group had eaten only 1 g more of IMB than the VAGX-VEH group (NS). We conclude that 1) the vagus is among the physiological systems involved in the anorectic responses to IMB and 2) intact vagal function is necessary for the full effect of 5-HT3 antagonists in alleviating the anorectic responses to IMB.