Groups of newborn Wistar rats received daily 1-desamino-8-D-arginine-vasopressin (DDAVP), oxytocin (OXT), hypertonic saline or normal saline for 14 days from day 1 to day 14 of life. One or three months later they were trained in a maze for brightness discrimination (BD). A group of untreated adult male rats received posttrial DDAVP or normal saline for brightness discrimination. Subsequently all the retentions of BD were tested after one month. We found that the neonatal treatments with both DDAVP and hypertonic saline facilitated acquisition and subsequent maintenance of brightness discrimination in immature and mature rats, and also that posttreatment with DDAVP enhanced retention of BD in adult rats. Oxytocin and normal saline had no effect on these parameters. The results are interpreted as showing that endogenous AVP and its synthetic analog enhance the development and adult function of central neural substrates involved in learning behaviors.

Animals↗

PubMedDate not supplied

A non-invasive method for evaluating cirrhotic portal hypertension by administration of 99mTc-MIBI per rectum.

A study was performed to evaluate radio-isotopic imaging using technetium-99m hexakis 2-methoxyisobutyl isonitrile administered per rectum to assess portal collateral circulation. The heart-liver ratios (H/L; mean +/- standard deviation) in 15 controls, 13 cases of histologically confirmed viral hepatitis and 57 cirrhosis patients were 0.27 +/- 0.11, 0.43 +/- 0.14 and 1.00 +/- 0.28, respectively (P < 0.001). Among the cirrhosis patients those with the Child-Pugh classification A, B and C had H/L of 0.56 +/- 0.14, 1.00 +/- 0.20 and 1.19 +/- 0.26, respectively (P < 0.001). A high value of H/L was associated with a high risk of hepatic encephalopathy (1.25 +/- 0.17, P < 0.01) and oesophageal varices (1.02 +/- 0.20, P < 0.01). There were associations between H/L and serum bilirubin (P < 0.01), albumin (P < 0.05) and prothrombin time (P < 0.05). The results also showed a good correlation between H/L and portal vein pressure measured during operation in 13 patients (P < 0.001, r = 0.87). The regression equation: y = 6.77 + 32.5 H/L, allowed portal vein pressure to be estimated. The prognostic value of the test was supported by the fact that good correlations were observed between the H/L ratio and widely accepted prognostic classification (Child-Pugh). It is suggested that this new method could be a reliable non-invasive way to give an indication of the degree of portasystemic shunting to evaluate the prognosis and to follow up the effects of medications for reducing portal hypertension in patients with cirrhotic portal hypertension.

Administration, Rectal↗