Tectal neurons of the crucian carp were functionally and morphologically identified by recording their electrical activity and simultaneously injecting dye (Procion yellow). Among intrinsic tectal neurons, visual neurons successfully stained with dye were pyramidal, pyriform and uncategorized neurons. The stained intrinsic tectal neurons were classified into 4 types, according to their visual response properties, i.e. sustained, dimming, transient and other response types. In 23 stained neurons we studied, no correlation was established between response properties and morphology of tectal neurons. In stained pyramidal neurons, the following receptive field (RF) organization could be recognized: (1) on-center, off-surround; off-center, on-surround; both with a small RF; and (2) excitatory or inhibitory center only, with a large RF.

Animals↗

PubMed1980

Mechanism of elevation of serum alkaline phosphatase activity in biliary obstruction: an experimental study.

Bile duct ligation in rats increased alkaline phosphatase activity in serum and liver. In the serum, the activity reached a peak 24 h after bile duct ligation, earlier than in the liver. This finding indicates that the elevation of serum alkaline phosphatase activity is not due to simple overspill of this enzyme from the liver into the circulation. An electrophoretic study, employing polyacrylamide gel with Triton X-100, and a gel filtration study disclosed that 24 h after bile duct ligation the serum contained a high molecular weight form of alkaline phosphatase in addition to the hepatic and intestinal isoenzymes. The high molecular weight form was also found in bile, indicating that regurgitation of bile contributed to the increase in alkaline phosphatase activity in the serum. The absence of the high molecular weight alkaline phosphatase in the sera of rats with intrahepatic cholestasis induced by alpha-naphthylisothiocyanate suggests that, in this type of cholestasis, regurgitation of bile alkaline phosphatase does not play an important role in the elevation of serum alkaline phosphatase activity. These findings indicate that the high molecular weight alkaline phosphatase in serum is a useful diagnostic marker of biliary obstruction.

1-Naphthylisothiocyanate↗

PubMed1980

Stimulation of DNA synthesis by heated human serum in primary culture normal adult rat hepatocytes.

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Animals↗

PubMed1980

Organization of the cortico-caudate projections. A horseradish peroxidase study in the cat.

The organization of the cortico-caudate projection neurones in the cerebral cortex was demonstrated by utilizing retrograde axonal transport of horseradish peroxidase (HRP) in the cat. Following injection of HRP into the head portion of the caudate nucleus, cortical labelled cells with HRP could be divided into two groups, consisting of smaller and larger pyramidal neurones. The location of the smaller neurones in the cortex was mainly in layer III, while that of the larger neurones was exclusively in layer V. In the cerebral cortex ipsilateral to the HRP-injected side, labelled cells belonging to the smaller group were distributed mostly in area 6 and occasionally in areas 4 and 5. Labelled cells belonging to the larger group were located exclusively in area 6. In the contralateral cortex, labelled cells were all smaller in size and distributed only in area 6. Referring to recent physiological as well as anatomical data, the smaller, labelled pyramidal cells were considered to be the proper, direct cortico-caudate neurones. The larger, labelled pyramidal cells were regarded as cortico-caudate projection neurones also sending axons to the lower brainstem and/or the spinal cord. The results of the present study indicate the existence of a close relationship between area 6 (premotor area) of the cerebral cortex and the caudate nucleus.

Afferent Pathways↗

PubMed1980

Vasoactive intestinal polypeptide stimulation of cyclic AMP formation in rat central nervous system.

Vasoactive intestinal polypeptide (VIP) stimulated cyclic AMP formation in the anterior pituitary, hypothalamus, pons and cerebral medulla of rat in vitro. The concentration of VIP above 10(-7) M significantly raised cyclic AMP level of these tissues with dose-dependency and the maximum stimulation of cyclic AMP formation was obtained at 5 min incubation. This stimulatory effect of VIP was not inhibited by propranolol or somatostatin. However, no enhancement of hormone release from the anterior pituitary or hypothalamus into the incubation medium by VIP was observed. These results suggest that VIP may act through adenylate cyclase in specific areas of rat central nervous system independent of beta-adrenergic receptor, but it may not necessarily be related to hormone release from the anterior pituitary or hypothalamus.

Animals↗

PubMed1980

Effect of BCG on hepatocarcinogenesis of the rat induced by 3'-methyl-4-(dimethylamino)azobenzene.

The effect of BCG, an immunopotentiator, on the hepatocarcinogenesis of the rat induced by 3'-methyl-4-(dimethylamino)azobenzene (3'-Me-DAB) was investigated. After administration of 3'-Me-DAB for 6 weeks, BCG was injected to the rats at 2-week intervals for 50 weeks and the serial determinations of serum alpha-fetoprotein and morphological examination of the liver were made. In the control group, the second rise of serum alpha-fetoprotein, which reflected the occurrence of hepatoma, was seen at about 12 weeks after discontinuance of 3'-Me-DAB. On the other hand, the second rise of serum alpha-fetoprotein in the group treated with BCG was delayed about 10 weeks compared to control group, although there was no significant difference in the final incidence of hepatomas between these two groups. Infiltration of the lymphocytes was observed in the liver of rats treated with BCG without hepatoma. BCG seems to have an inhibitory effect on 3'-Me-DAB carcinogenesis of the rat, possibly by stimulating the cell-mediated immunity, although it is not strong enough to prevent the occurrence of hepatoma completely.

Animals↗