The role of D2 dopamine receptors in oxytocin induced place preference and anxiolytic effect

Neuropeptide oxytocin (OT) is involved in the regulation of social and non-social behaviour. The central nucleus of amygdala (CeA), part of the limbic system, plays an important role in learning, memory, anxiety and reinforcing mechanisms. CeA has been shown to be rich in OT receptors in rodents. Our previous findings indicated that OT in the rat CeA has a dose dependent rewarding and anxiolytic effect. The aim of our present study was to examine in the CeA the possible interaction of OT and D2 dopamine (DA) receptor antagonist Sulpiride on reinforcement in place preference test and on anxiety in elevated plus maze test. Wistar rats were microinjected bilaterally with 10 ng OT. In different group of animals 4 μg D2 DA receptor antagonist was applied. Other animals received D2 DA receptor antagonist 15 min before 10 ng OT treatment or vehicle solution into the CeA. Rats receiving 10 ng OT spent significantly longer time in the treatment quadrant during the test session in conditioned place preference test. Prior treatment with D2 DA receptor antagonist blocked the rewarding effects of OT. Antagonist in itself did not influence the time rats spent in the treatment quadrant. In elevated plus maze test, rats receiving 10 ng OT spent significantly longer time on the open arms. Prior treatment with D2 DA receptor antagonist blocked the effects of OT. Our results show that DA system plays a role in positive reinforcing and anxiolytic effects of OT because D2 DA receptor antagonist can block these actions.

[Pyridimocarbamate (prodectin)-induced acute liver damage, cirrhosis and primary liver cancer--accidental finding?]

Authors have verified during the postmortem of a 60-year-old woman, in addition to clinically manifested vascularly and parenchymally decompensated cirrhosis a small hepatocellular carcinoma with signs of vascularization. The patient received since four years pyridinolcarbamate (Prodectin) because of obliterating peripheral arteriosclerosis. During treatment, icterus occurred the drug-induced nature of which was proved by the provocation-test. Owing to the known hepatotoxic effect of pyridinolcarbamate the question must be raised concerning a possible causal relationship between the acute hepatic damage having occurred four years ago and the cirrhosis and cancer observed in the autopsy material. The reporting of this case was aimed at drawing attention to such a possibility.

[Morphologic observations in liver damage in patients taking Depressan (dihydralazinum sulfuricum)]

Authors studied a 56 year old male and a 47 year old female patient having taken an antihypertonic drug for two and a half month and one year respectively observed acute HBsAg-negative liver disease. In the needle biopsy specimen obtained on the 8th day (at the male patient) and on the 10th day (at the female) of the onset of jaundice severe centrilobular liver cell necrosis was found, which in the first case was accompanied by "bridging" necrosis. In the necrosis-free areas hydropic and fatty degeneration of different degree and also cholestasis occurred. The mild local and portobiliar inflammatory reaction consisted of mononuclear cells, neutrophil- and eosinophil granulocytes. Pathogenetic role of the drug has been proved by a provocation test. Authors call attention to the fact, that Depressan represents another drug, being in use in this country, which causes centrilobular liver cell necrosis.

Hepatitis B virus, cirrhosis and primary carcinoma of the liver. An electron microscopic study

The core and coat of hepatitis B virus were found by electron microscopy in parenchymal cells of a liver biopsy from a 61 year old man with chronic active hepatitis and cirrhosis of the liver. Laparoscopy, 35 days after liver biopsy, and autopsy 42 days later confirmed the cirrhosis and showed in addition a well differentiated hepatoma. The possibility of a viral aetiology for the cirrhosis and primary carcinoma of the liver is considered.

Immunosuppressive therapy and virus-cores in HBAg-positive chronic hepatitis

Three liver biopsies were carried out in a case of chronic active hepatitis with persistent HB-antigenemia. Virus-cores could not be detected in the liver cell nuclei by electron microscopy before immunosuppressive therapy. Intranuclear, ring-shaped virus-cores of 20-25 nm diameter appeared in almost every hepatocyte examined during immunosuppression.

[Intranuclear particles in a patient with chronic aggressive hepatitis treated by immunosuppression]

After an acute HbsAg-positive transfusion hepatitis the patient--a 40 years old women--remained seropositive. Later a chronic aggressive hepatitis have developed, which could be evidenced by histological findings. On the electron microphage in the nucleus of liver cells ring-shaped particules 20--25 nm in diameter were revealed. They consisted of granula 2--3 nm in diameter. These particules are considered to represent so called virus-nuclei (core of the virus B of hepatitis) and to play a pathogenic role. These particules are commonly present and easily found. The great number of them--according to author's opinion--can be explained by the effect of immunosuppressive therapy.

[Electron miscroscopic liver changes in acute carbon tetrachloride poisoning in man)]

Lesions of the liver revealed by light and electron microscopy at two young men, workers of the chemical industry are described. At one of the patients biopsy was performed twice at the other three times. Patient having jaundice were admitted to hospital because of the suspected acute viral hepatitis. Laboratory findings have shown an acute parenchymal lesion. By light microscopy at one of them mid-zonal, at the other centro-lobular necrosis of hepatic cells further lipoid droplets of the cytoplasma of hepatocytes were revealed. Electronmicroscopically in the first biopsy specimens, and at one of the ptients at the second biopsy as well mostly damage to the mitochondria (enormous osmiophilia of the matrix, presence of osmiophil granules) and enlargement of the tubules of the endoplasmic reticulum could be seen. The controll clinical and morphological findings evidenced the reversible character of the process. Authors stress the differences existing between hepatic lesions caused by CCl4 at different persons on one side, and at rat and human liver on the other.