Decreased serotonin S2 and increased dopamine D2 receptors in chronic schizophrenics.

Serotonin S2 and dopamine D2 receptors in the prefrontal cortex and caudate nucleus of postmortem brains of chronic schizophrenics were studied using 3H-ketanserin and 3H-spiperone, respectively. In the prefrontal cortex of schizophrenics, we found a significant decrease in the maximum number of 3H-ketanserin binding sites (Bmax), with no change in the dissociation constant (Kd). Conversely, both Bmax and Kd of 3H-spiperone binding to the caudate nucleus were significantly increased in the schizophrenic patients. There were no differences in receptor indices between patients who were taking neuroleptics until their death and those who had taken none for 2 months or more prior to death. These findings suggest that alterations in S2 receptors in the prefrontal cortex may reflect the disease process, per se, and that the increase in the number of D2 receptors in the caudate nucleus of schizophrenics is not due solely to neuroleptic medication.

Development of flexible ventriculoscope (Yamadori-type VII) and its application to experimental animals.

We developed a new ventriculoscope (Yamadori-type VII), a 2.1 mm calibrated fiberscope with a monopolar coagulator, that can be inserted from the cisterna cerebellomedullaris into the third cerebral ventricle of experimental animals, like dogs. With the improved performance of the neuroendoscope compared to its prototype, Yamadori III, it was possible to inspect clearly and to produce electrocoagulative lesions accurately on any part of the intraventricular structures with minimal injury to nearby vital brain areas.

An experimental anatomical study on the optic nerve fibers in the rat: courses of the accessory optic tract.

By means of silver impregnation and an HRP method, courses of the accessory optic tract were examined in albino and pigmented rats. The accessory optic tract is composed of 3 fasciculi: anterior, lateral and dorsal. The anterior fasciculus gives off fibers to the subthalamic nucleus and terminates in the medial terminal nucleus. The lateral fasciculus branches from the main optic tract at the level of the ventral nucleus of the lateral geniculate body and descends the lateral surface of the crus cerebri to enter the medial terminal nucleus after contributing a few fibers to the lateral terminal nucleus. The dorsal fasciculus originates from the brachium colliculi superioris and descends the posterior surface of the medial geniculate body and the posterolateral surface of the crus cerebri as an independent fasciculus to enter the medial terminal nucleus. This fasciculus supplies many fibers to the dorsal terminal nucleus.

Corticonuclear and corticovestibular projections from the uvula in the albino rat: differential projections from sublobuli of the uvula.

The organization of the corticonuclear and corticovestibular projections from the uvula was investigated in the albino rat by an autoradiographic method. The corticonuclear fibers from sublobule a of the uvula terminated in the caudoventral part of the medial cerebellar nucleus, and the caudomedial part of the posterior interpositus nucleus with mediolateral topography. The medial and lateral portions of the sublobule projected to the medial cerebellar and posterior interpositus nuclei, respectively. The corticovestibular fibers from sublobule a terminated in the dorsal and rostral parts of the superior vestibular nucleus, the dorsal part of the lateral vestibular nucleus, and the caudomedial part of the spinal vestibular nucleus. However, the corticonuclear fibers from sublobuli b and c of the uvula terminated additionally in the ventromedial part of the lateral cerebellar nucleus, while the corticovestibular fibers from these sublobuli terminated additionally in the subnucleus y of the vestibular complex, with probable termination in the medial vestibular nucleus. The cortical region which sent efferent projections to the ventromedial part of the lateral cerebellar nucleus and the subnucleus y was located laterally in sublobuli b and c of the uvula. These differential projection patterns from the dorsal and ventral sublobuli suggest the difference of the functional correlates between the sublobuli in the uvula.

A study of the retinal ganglion cell which has an uncrossed bifurcating axon in the albino rat.

Injection of the fluorescent tracers, Evans blue (EB) and Primulin (Pr), or EB and 4',6-diamino-2-phenylindol dihydrochloride (DAPI), respectively, into the dorsal nucleus of the lateral geniculate body and the superior colliculus on the ipsilateral side have demonstrated the existence of retinal ganglion cells having uncrossed bifurcating axons in the albino rat. Our fluorescent labeling study confirms the existence of double-labeled cells, namely, retinal ganglion cells having bifurcating axons, in the peripheral temporoventral half (temporoventral crescent) of the ipsilateral retina, coupled with the single-labeled cells from each structure. A percentage estimation of these three kinds of labeled cells revealed that the double-labeled cells greatly occupy a majority of the entire labeled cells and no ostensible difference was evident in the proportion of double-labeled cells to the entire labeled cells between both the ipsilaterally and contralaterally projecting cell groups.

A retrograde double-labelling study of retinal ganglion cells that project ipsilaterally to vLGN and LPN rather than dLGN and SC, in albino rat.

We studied ipsilaterally projecting, double-labeled retinal ganglion cells that have bifurcating axons by retrograde fluorescent double-labeling in albino rats. Ten albino (Wistar, Japan Ceca) rats of either sex, weighing 350-400 g were used. With the rats in a state of deep anesthesia, we pressure-injected 0.02 microliter of 15% Evans blue (EB) into the right ventral lateral geniculate nucleus (vLGN), and 4% Fluoro-gold (FG) iontophoretically into the right posterior lateral thalamic nucleus (LP). The animals were perfused with formol-saline 48-72 h later and both the brain and eyes were exercised. The brain was sectioned coronally, and each retina was removed and mounted flat on a glass slide. Double-labeled cells were found in the ventral temporal crescent of the retina. In one animal and total number of ipsilaterally labeled cells was 566, and the percentage of double-labeled vLGN and LP projecting cells, single-labeled vLGN projecting cells, and single-labeled LP projecting cells were 29.8, 58.8 and 11.3, respectively.

Demonstration of direct input from the retina to the lateral habenular nucleus in the albino rat.

The projection from the retina to the habenular complex was studied using fluorescent retrograde tracers in the albino rat (Wistar, Japan Clea). Following separate unilateral injections of Fluoro-Gold (FG), Fluoro-Ruby (FR), or 4-acetamido,4- isothiocyanostilbene-2,2'-disulfonic acid (SITS) into the lateral habenular nucleus (LHB), a small population of ganglion cells was labeled sporadically, predominantly those in the nasal retina contralateral to each injection site. Most of them were small cells, ranging from 9 to 16 mu m in diameter, roughly corresponding to the type III ganglion cell in the rat retina. Additionally, all of the structures previously described as regions projecting to the LHB were confirmed. Upon re-examination of previous brain sections of albino rats which had undergone monocular enucleation, degenerating retinal nerve axons and/or their terminals, stained by a modified selective silver impregnation method, were observed in the well-documented end regions of retinal afferents as well as the LHB. The degenerating retino-habenular nerve terminals were distributed sparsely and restricted mainly to the caudal part of the LHB contralateral to the side of ocular enucleation. The present experimental data provide evidence for the existence of a non-image forming retino-habenular pathway in the albino rat. We suggest that, besides serving as a point of convergence for some of the major conduction channels of the limbic and striatal systems, the LHB may play more general integrative roles, including participation in the integration of visual information.

A retrograde fluorescent-labeling study of direct relationship between the limbic (anterodorsal and anteroventral thalamic nuclei) and the visual system in the albino rat.

Injecting different fluorescent tracers into the right anterodorsal (AD)/anteroventral (AV) or AD/AV and the primary visual nuclei of dorsal lateral geniculate (dLGN) or superior colliculus (SC), a direct projection from the left retina to these anterior thalamic nuclei was ascertained in the central part of ventro-nasal retinal quadrant. Single-labeled cells were of small type. No double-labeled cells were demonstrated.

A retrograde double-labeling study of uni- and bilaterally projecting retinal ganglion cells that project to the superior colliculi after unilateral eye removal at birth in the albino rat.

By injecting Fluoro-Gold and Evans-Blue into the right and left superior colliculi of the normal adult albino rats, bilaterally projecting retinal ganglion cells were labeled in the ventrotemporal crescent accounting for 37.9% of all the labeled cells, whereas in 0- and 5-day unilaterally enucleated rats these were found in the lower half of the retina accounting for 64.8% and 80.6%, respectively. Furthermore, they tended to have larger somata (type I cells).

Correlation between different types of retinal ganglion cells and their projection pattern in the albino rat.

Injecting Fluoro-Gold (FG) and Evans-Blue (EB) into the right dLGN and SC in the adult albino rat, ipsilaterally projecting double-labeled retinal ganglion cells were mainly seen in the ventrotemporal crescent. They were mainly large sized cells. The ipsilaterally projecting double-labeled cells tended to have larger somata than the single- and double-labeled cells projecting to the contralateral superior colliculus and/or dorsal nucleus of the lateral geniculate body.

Bifurcated projections of retinal ganglion cells bilaterally innervate the lateral geniculate nuclei in the cat.

Cats were injected with the fluorescent retrograde tracers, Fluoro-Gold (FG) and Evans Blue (EB), into the left and right lateral geniculate nuclei (LGN), respectively. About 4.56% of the ganglion cells in the temporal retina were double-labeled by these dyes. 4.7% of these cells were of the large type, 30.3% were of the medium type, and 65% were classified as cells of the small type. These results indicate that members of all three ganglion cell size classes, mainly those of small type, bilaterally innervate the LGN via axonal bifurcation.

Fluoro-Green and Fluoro-Red: two new fluorescent retrograde tracers with a number of unique properties.

As a means of improving nerve tract-tracing in the peripheral and central nervous systems we experimented with two (retrograde) fluorescent emulsions, which we have tentatively named Fluoro-Green (FGr) and Fluoro-Red (FRe), and which we believe possess the following seven advantages: (1) they show little diffusion beyond the injection site; (2) their excitation/emission characteristics allow their use in double-tracing experiments; (3) they do not 'leak' from labeled cells; (4) their fluorescence is presented as large granules in the cytoplasm and its processes; (5) the fluorescence lasts for a sufficiently long time to permit repeated observation; (6) they may be used in combination with a wide variety of other neuroanatomical tracing methods; (7) they are economical, non-toxic and easy to utilize.

A study of double-labeled retinal ganglion cells from the superior colliculus in the developing albino rat.

We studied the distribution pattern and percentage of bilaterally projecting, double-labeled retinal ganglion cells in the albino rat by the retrograde fluorescent double labeling. Forty-five albino (Wistar, Japan Clea) rats of either sex and of different stage of development ranging in age from the day of birth (Day 0) to Day 30, were used. With the rats under deep anesthesia, we pressure injected 0.02 microliter of 15% Evans blue (EB) and 0.02 microliter of 4% Fluoro-gold (FG) into the right and left superior colliculi, respectively; for rats older than 5 days, the volume of each tracer was 0.04 microliter. The animals were perfused with formol-saline 48 to 72 h later and the brain and eyeballs were excised and sectioned. Double-labeled cells were found over almost the entire retina, with the concentration in the lower temporal crescent in rats up to day 1; concentration gradually shifted to the ventral half between days 5 and 10. After day 15, double-labeled cells were found only in the ventral-temporal crescent of the retina, which is the pattern in the adult rats. The percentages of retinal ganglion cells that were double-labeled at days 0, 1, 5, 7, 10, 15, 20, 25 and 30 were 60.2, 51.6, 60.5, 57.6, 62.2, 60.7, 55.7, 45.2, and 39.1, respectively. After day 10, the percentage of such cells decreased steadily.

Retrograde fluorescent double-labeling study of bilaterally projecting retinal ganglion cells in albino rats at different stages of development.

Injection of the fluorescent tracers 10% Evans blue (EB) and 4% fluoro-gold (FG) into the right and the left dorsal lateral geniculate nucleus, respectively, of albino rats at different stages of development demonstrated the presence of double-labeled retinal ganglion cells that projected bilaterally into both the dorsal lateral geniculate nuclei (dLGN). Findings confirmed that the distribution of these double-labeled cells was gradually reduced after birth, being confined to the peripheral temporoventral quarter (temporal-ventral crescent) of the retina after postnatal day 15. We estimated the proportion of double-labeled cells to total labeled cells in the same area at different stages of development (0-90 days); values ranged from 35.3% in the neonate to 5.27% in the adult rat which suggests that the majority of double-labeled cells and/or their axons were lost early in development. That a small number of ganglion cells were observed to project bilaterally in the adult rats suggested that these cells conduct the same visual information to both hemispheres throughout the animal's life.

Course of the accessory optic fascicular fibers in the rat.

The courses of fibers in the dorsal and lateral fasciculi of the accessory optic tract were studied in the rat by means of a selective silver impregnation method for degenerating nerve fibers and Mesulam's HRP method. The results indicate that except for a moderate number of fibers entering the dorsal terminal nucleus and the lateral terminal nucleus respectively, all optic fibers constituting the dorsal and lateral fasciculi descend the lateral surface of the brain to terminate in the medial terminal nucleus. No ascending optic nerve fiber to the dorsal or lateral terminal nucleus is included in these fasciculi.

Retrograde double-labeling study of retinal ganglion cells from the ipsilateral vLGN and SC in the albino rat.

Retinal ganglion cells with branches to the ipsilateral ventral lateral geniculate nucleus (vLGN) and superior colliculus (SC) were studied by retrograde fluorescent double-labeling. Double-labeled cells were found in the ventral temporal crescent of the retina, with a few ipsilaterally projecting single-labeled cells scattered in this area. Single-labeled vLGN-projecting cells were found predominantly in the ventral-temporal crescent and to a lesser extent in the temporal and dorsotemporal octant. SC-projecting cells were present predominantly in the ventral-temporal crescent and to a lesser extent in the ventral and ventronasal octant. Our best animal model had 2200 ipsilaterally labeled cells. There were 451 (20.5%) double-labeled vLGN and SC-projecting cells, 561 (25.5%) single-labeled vLGN-projecting cells, and 1186 (53.9%) single-labeled SC-projecting cells.

Cerebral ischemia affects glucose transporter kinetics across rat brain microvascular endothelium: quantitative analysis by an in situ brain perfusion method.

BACKGROUND: It has been reported that cerebral ischemia induces a dissociation between cerebral blood flow and blood-brain barrier glucose transport, but mechanisms of the dissociation are not yet clearly understood. Recent immunohistochemical studies reveal discrepancies of the results between physiologic and immunochemical studies. The purpose of this study was to quantify changes of the blood-brain barrier glucose transporter kinetics following cerebral ischemia by an in situ brain perfusion technique. METHODS: Fifty-six adult male Sprague-Dawley rats were divided into control and ischemia groups, and four-vessel occlusion was done as an ischemic insult. To obtain regional capillary permeability surface area products of glucose and regional perfusion fluid flow rates, the perfusion fluid (HCO3-buffered saline) was dually labeled with [14C]-2-Deoxyglucose and [3H]-Diazepam, and the brain was perfused at a constant rate via the external carotid artery. After sampling tissues from three regions (frontal, frontoparietal lobe, and caudoputamen), dual scintillation counting was performed. From the results, we determined kinetic parameters, including Vmax, Km, and Kd as described in the Michaelis-Menten equation, by weighted nonlinear least squares method. RESULTS: In the ischemia group, the affinity (1/Km) and the maximum glucose transport rate (Vmax) decreased significantly. CONCLUSIONS: The results suggest that severe cerebral ischemia down-regulates the blood-brain barrier glucose transporter kinetics, and the discrepancies between physiologic and immunohistochemical studies may be derived from redistribution of transporters, some deformation of transporters, production of some inhibitors, recruitment of capillaries with different types of transporters, and/or the effect of surrounding glial reaction.

Atypical X-linked agammaglobulinemia diagnosed in three adults.

OBJECT: X-linked agammaglobulinemia (XLA) is one of the most common humoral immunodeficiencies characterized from childhood by the absence of peripheral B lymphocytes, reduced levels of serum immunoglobulins and recurrent and severe bacterial infections. These characteristics are the result of Bruton's tyrosine kinase (Btk) protein deficiency in peripheral B lymphocytes. In addition to typical XLA, several atypical cases have been recognized, who exhibited mild or even no clinical symptoms, although they were definitely deficient in Btk protein (atypical XLA). In these patients peripheral B lymphocytes and serum immunoglobulins (Igs) are detectable though at a lower level than in normal people. To clarify the discrepancies between the Btk gene mutations and the phenotypes more atypical patients should be examined. In this study we evaluated the cytoplasmic Btk protein in peripheral monocytes of some hypogammaglobulinemia adults by means of flowcytometric analysis. MATERIALS AND METHODS: Heparinized venous blood samples were collected from some hypogammaglobulinemia adults. Mononuclear cells were separated from their blood and first reacted with a phycoerythrin-labeled CD14 monoclonal antibody (MoAb) (staining of monocyte membrane). Next, the cells were fixed and permeabilized. And then these permeabilized cells were reacted with an anti-Btk MoAb (staining of cytoplasmic Btk protein) and incubated with a FITC-conjugated goat antimouse IgG1. The double-stained cells were analyzed on a flowcytometer. RESULTS AND CONCLUSION: By means of flowcytometric analysis we diagnosed three hypogammaglobulinemia adults as XLA, who did not show typical clinical progress of XLA. Advancements in diagnostic methods has facilitated a prompt and definite diagnosis of this disease.

A [14C]2-deoxy-D-glucose study of brain structures related to conditioned emotional response in the rat.

We used [14C]2-deoxy-D-glucose (2-DG) to determine activated brain structures related to conditioned emotional response (CER) in rats. The experimental groups were conditioned with paired conditioned-stimulus (CS; flickering light and clicking sound) and unconditioned-stimulus (US; foot-shock) for either 25 or 50 trials. The control groups were also exposed to the same stimuli but in unpaired or random sequence. Two days after conditioning, rats were intravenously injected with [14C]2-DG and then exposed to the CS alone (CER test) in a shock box. Mean optical densities of 44 brain structures were measured with an autoradiogram, and their optical density ratios were compared by 2-by-2 (paired vs unpaired and 25 vs 50 trials) analysis of variance. Those brain structures were of 2 types; the first type showed similar changes of 2-DG uptake in both paired and unpaired groups (Areas 7 and 40 of the cerebral cortex, the habenula and the colliculus inferior), while the second type showed that 2-DG uptake increased in the paired groups but decreased in the unpaired groups (Areas 24, 10, 6, 4 and 3 of the cerebral cortex), as a function of number of trials. Because changes of 2-DG uptake in the first type structures and in Areas 3, 4 and 6 of the second type structures are regarded to reflect learning-nonspecific effects and task- or stimuli-related symmetrical activation, respectively, we concluded that Areas 24 (anterior cingulate cortex) and 10 (prefrontal cortex) were specifically related to conditioned emotional response.

Phylogenetic development of brain and brain sulci in primates.

The purpose of this study was to investigate the phylogenetic development of the cerebrum and cerebral sulcus in primates. The species selected were Macacus, Hylobates, Pan and Homo sapiens. These samples are classified as old world monkeys (Cercopithecidae), anthropoid apes (Pongidae), and Man (Hominidae). Although these four species divided up and went their separate ways from about the Oligocene era, the pattern of the cerebral sulci is similar. Of various cerebral sulci, the cingulate and calcarine sulci were selected, because they run on the medial surface of the cerebrum. The length of these sulci and fronto-occipital (FO) length were measured by a "cotton-thread" method. With the increase of size (FO-length) and weight of the brain, these sulci became longer, but there were no significant differences in the ratio of the calcarine sulcus to the FO-length among these four species. On the contrary, the ratio of the cingulate sulcus to the FO-length in Pan and Homo sapiens was significantly higher than in the other species, indicating that this ratio becomes higher with the phylogenetic development. The results of the present study suggest that the ratios of these sulci to the FO-length can be used as good indices to assess the degree of the phylogenetic development of the brain.