Emotional behavior and the brain.

Basic behaviors were defined as those controlled by the hypothalamus, and emotion and instinct were defined as the drives of such behaviors. A learning method showed that fear-escape is obtained from the medial hypothalamic area except for the ventromedial nucleus. It was suggested that some neural systems responsible for threat, attack, rush and retreat are overlapped in the ventromedial nucleus. Functions of the amygdala and the septum were discussed in relation to hypothalamic activity in emotional behavior. A behavioral sequence composed of stimulation, classical conditioning, drive, reward learning and behavior was discussed, and learning, anxiety in neuroses and Morita therapy were examined from the viewpoint of the behavioral sequence.     

Novel polymorphism in the coding region of the IL-13 receptor alpha' gene: association study with atopic asthma in the Japanese population

Interleukin (IL)-4 and IL-13 play key roles in the development of atopic asthma. The IL-13 receptor (R) alpha' chain is a component of both IL-4R and IL-13R complexes. By screening the whole coding region of the IL-13Ralpha' gene for polymorphisms, we identified a new polymorphism at nucleotide position 1050 from the ATG start codon. The allelic frequency of the C/T polymorphism in the Japanese population was found to be 0.97:0.03. Because of the low frequency of the T allele, the association study failed to indicate any significant association between this polymorphism and atopic asthma in the Japanese population. Further studies are required in other racial groups with higher frequencies of this polymorphism to elucidate the association.     

Creation and use of a composite polyurethane-expanded polytetrafluoroethylene graft for hemodialysis access

The Thoratec (Vectra) polyurethane vascular access graft (TPVA) is among the most recent additions to the list of materials used to construct prosthetic grafts for vascular access during hemodialysis. We give the TPVA very high marks, and recognize the utility of such a graft for use in hemodialysis. However, the strong elasticity of this graft can lead to unexpected complications after suturing. We devised a new surgical method using a TPVA-ePTFE (expanded polytetrafluoroethylene) composite graft, substituting the anastomosis section of the TPVA with a portion of ePTFE graft material, and have been able to overcome most of the TPVA's potential problems. We herein describe the technique.     

Feeding with powdered diet after weaning increases visuospatial ability in association with increases in the expression of N-methyl-D-aspartate receptors in the hippocampus of female rats

We determined whether feeding with powdered diet improved the visuospatial ability in female rats by checking the expression of N-methyl-D-aspartate receptor (NMDAR) subunit 1 (NR1) mRNA in the hippocampus. In rats fed standard pelleted diet, males performed better than females in a radial 8-arm maze task as we reported previously. We found that the expression of NR1 mRNA, which may be the key mediator in visuospatial ability in the hippocampus, was also higher in males than in females. However, in rats fed powdered diet, no sex difference was seen in the radial 8-arm maze task and the expression of NR1 mRNA in the hippocampus, since feeding with powdered diet improved the visuospatial ability with increases in the expression of NR1 mRNA in the hippocampus in females. We suggest that the sex difference in visuospatial ability is at least in part due to feeding conditions.     

Kinetics and staining properties of mast cells proliferating in rat small intestine tunica muscularis and subserosa following infection with Nippostrongylus brasiliensis

Mucosal mast-cell hyperplasia occurs in the rat small intestine mucosa after infection with Nippostrongylus brasiliensis. In the present study, the number of mast cells was found to increase in the muscularis and subserosa as well as in the mucosa of rat small intestines 2-3 weeks after infection with this nematode. Mast cells in the muscularis were stained blue by the alcian blue/safranin sequence and did not bind berberine sulfate. The staining was blocked when tissues were fixed in neutral formalin. The increase in mast cells was transient and gradually disappeared; the half-life was 40 days. After an intravenous administration of compound 48/80, mast cells in the muscularis did not discharge granules. The results indicate that these mast cells were of the mucosal type. The mast cell phenotype in the muscularis did not change even 12 weeks after infection. Mast cells in the subserosal tissue were first of the mucosal type as were those in muscularis. After 8-12 weeks, however, many subserosal mast cells became positive for berberine sulfate and safranin. These results show that mucosal-type mast cells do not undergo phenotypic changes during the period of observation when these cells appear in the muscularis but the phenotypic expression may change as the cells arise in subserosal tissue.     

Functional organization of premotor neurons in the cat medial vestibular nucleus related to slow and fast phases of nystagmus

Summary Extracellular spikes were recorded from secondary vestibular neurons in the cat medial vestibular nucleus (MVN) and were identified as type I or II neurons by horizontal rotation. Type I neurons were further classified as excitatory or inhibitory premotor neurons on the basis of their axonal termination in the contralateral or ipsilateral abducens nucleus, demonstrated by spike-triggered averaging of abducens nerve discharges, or by antidromic activation using systematic microstimulation within the abducens nucleus.Both excitatory and inhibitory premotor type I MVN neurons exhibited a rhythmic modulation of their firing rate in association with nystagmus elicited by rotation or electrical stimulation of the vestibular nerve. Their tonic activity during the slow phase was suppressed at the quick phase directed to the ipsilateral side.Excitatory type I MVN neurons terminating in the contralateral abducens nucleus sent collateral axons to the contralateral MVN. These commissural neurons also showed a nystagmus-related discharge pattern.Type II MVN neurons activated at short latency by stimulation of the contralateral vestibular nerve exhibited burst discharges when the activity of ipsilateral type I neurons was suppressed at the quick phase. These type II neurons made monosynaptic inhibitory connections with type I neurons as shown by the post-spike average of the membrane potential of secondary MVN neurons triggered from spikes of single type II neurons. Thus, the inhibitory action originating from burst activity of type II MVN neurons contributes to suppression of type I premotor MVN neurons during fast eye movements.Supported by Grant-in-Aid for Scientific Research No. 248106 from Japan Ministry of Education, Science and Culture. Dr. Schor was supported by the Research Fellowship of Japan Society for the Promotion of Science (JSPS)     

Fine structure of the myotendinous junction and “terminal coupling” in the skeletal muscle of the lamprey,Lampetra japonica

The myotendinous junction in the skeletal muscle of adult lamprey Lampetra japonica was studied with an electron microscope. Numerous finger-like sarcolemmal invaginations were present at the ends of muscle fibers to form the myotendinous junction. Parietal fibers of each muscle unit showed more closely distributed sarcolemmal invaginations than central fibers. Features of the myotendinous junction. Parietal fibers of each muscle unit showed more closely distributed sarcolemmal invaginations than central fibers. Features of the myotendinous junction generally conform to the accounts in the literature. The sarcolemmal invagination was covered on its sarcoplasmic aspect by the connecting filament layer and the dense amorphous attachment layer, and on the extracellular aspect by the intermediary layer and the external lamina with collagen fibrils arising from the myosepta. Sarcolemmal invaginations were sometimes seen to consist of a pair of sarcolemmas of adjacent muscle fibers within a muscle unit, which is characteristic to the myotendinous junction of lamprey. It is noteworthy that the connecting filament layer is much thinner than that, e.g., in the tadpole tail muscles (Nakao, '74). Furthermore, it is much thicker in the parietal fibers than in the central fibers. The sarcolemma of the terminal segment of the invagination frequently showed specific coupling with cisterns of the sarcoplasmic reticulum (terminal coupling). The external lamina is partially or completely deficient in the terminal segment of sarcolemmal invaginations which form terminal couplings so that collagen fibrils contained in the invagination appear to be in direct contact with the sarcolemma; however, definite relationships of collagen fibrils with the sarcolemma and the external lamina in the terminal segment of invagination still remain obscure. This type of coupling is considered to play a role in the coupling of excitation to contraction of muscle fibers as triads and diads.