To investigate the role of the hippocampal formation (HF) in feeding behavior, single neuron activity in the monkey HF was recorded during performance of an operant task that included food/nonfood discrimination, drinking, and active avoidance. Of 837 neurons recorded in the HF, 155 responded to the sight of one or more objects. Of these, 82 responded to the sight of different objects with different response magnitudes, and some of these 82 responded predominantly to food-related (rewarding) objects or nonfood, aversive objects. The magnitude of response of neurons that responded predominantly to food was not necessarily correlated with the order of animal's preference for those kinds of food. For some neurons that responded predominantly to food or nonfood, effects of extinction or reversal learning on the neuronal responses were tested, and most of the neurons tested maintained their original responsiveness even after behavioral extinction or reversal learning was accomplished. The results suggest that these HF neurons may be involved in preservation of past information concerning food or nonfood.

Animals↗

PubMedDate not supplied

Red ginseng ameliorated place navigation deficits in young rats with hippocampal lesions and aged rats.

Effects of hippocampal lesions and aging on spatial learning and memory and ameliorating effects of red ginseng on learning deficits were investigated in the following two experiments: performance of young rats with selective hippocampal lesions with red ginseng by mouth (p.o.; Experiment 1) and aged rats with red ginseng (p.o.; Experiment 2) in the spatial tasks was compared with that of sham-operated or intact young rats. Each rat in these two behavioral experiments was tested with the three types of spatial-learning tasks (distance movement task, DMT; random-reward place search task, RRPST; and place-learning task, PLT) in a circular open field using intracranial self-stimulation as reward. The results in the DMT and RRPST tasks indicated that motivational and motor activity of young rats with hippocampal lesions with and without ginseng were not significantly different from that of sham-operated young rats in Experiment 1. However, young rats with hippocampal lesions displayed significant deficits in the PLT task. Treatment with red ginseng significantly ameliorated place-navigation deficits in young rats with hippocampal lesions on the PLT task. Similarly, red ginseng improved performance of aged rats on the PLT task in Experiment 2. The results, along with previous studies showing significant effects of red ginseng on the central nervous system, suggest that red ginseng ameliorates learning and memory deficits through effects on the central nervous system, partly through effects on the hippocampal formation.

Aging↗

PubMedDate not supplied

Ameliorative effects of a cognitive enhancer, T-588, on place learning deficits induced by transient forebrain ischemia in rats.

In the present study, we investigated the effect of (1R)-1-benzo[b]thiophen-5-yl-2-[2-(diethylamino)ethoxy]ethan-1-ol hydrochloride (T-588), a newly synthesized cognitive enhancer, on place learning deficits in rats with damage selective to the hippocampal CA1 subfield induced by transient forebrain ischemia. Three weeks after the ischemic insult, T-588 was daily administered (0.3 or 3.0 mg/kg/day po). Place learning was tested in a task in which the rat was required to alternatively visit two places located diametrically opposite each other in an open field. The ischemic rats without the treatment of T-588 displayed severe learning impairment in this task; their performance level was significantly inferior to that of the sham-operated rats. The treatment of T-588 improved dose-dependently the task performance in ischemic rats, although no apparent protective effects on ischemic damage were found histologically. These results suggested that T-588 has ameliorative effects on learning deficits induced by brain ischemia, which could be produced through enhancement of residual cognitive functions.

Animals↗

PubMedDate not supplied

Enhanced effects of combined bu-zhong-yi-qi-tang (TJ-41) and interleukin-18 on the production of tumour necrosis factor-alpha and interferon-gamma in human peripheral blood mononuclear cells.

Co-stimulatory molecules play important roles in immune responses. We investigated the effect of Bu-Zhong-Yi-Qi-Tang (TJ-41) on the expression of intercellular adhesion molecule-1 (ICAM-1), B7.1 and B7.2 by peripheral blood mononuclear cells stimulated by interleukin-18 (IL-18) using fluorescence-activated cell sorter analysis. TJ-41 increased IL-18-induced ICAM-1 and B7.2 expression, resulting in enhanced production of tumour necrosis factor-alpha and interferon-gamma. These results suggest that TJ-41 enhances IL-18-induced cell-mediated immunity and may enhance host defence mechanisms against pathogens.

Antigens, CD↗

PubMedDate not supplied

Relationship between fatty liver and liver metastasis in rats given injection of rat colon cancer cell line.

BACKGROUND/AIMS: In a previous study we described that colorectal cancer patients with fatty liver had few liver metastases. To clarify whether this clinical finding is correct, we studied whether rats with fatty liver had infrequent liver metastases using experimental colon cancer. METHODOLOGY: Twenty male inbred F344/DuCrj rats (CLEA JAPAN Inc.), 8 weeks of age, were used in this study. These 20 rats were divided into two groups: Fatty liver group (FL group, n = 10) and Non-fatty liver group (NFL group, n = 10). 1.0 ml of tumor-cell suspension containing 1 x 10(7) RCN-9 cells was injected just under the capsule of the spleen. All animals were sacrificed 2 weeks after tumor inoculation. RESULTS: 1) Four rats out of 10 in the FL group (40%) had at least one metastatic nodule on the surface of the liver, while there were 10 rats with metastatic nodules in the NFL group (100%) (p < 0.01). 2) The ratio of the liver metastasis area against the largest section of the left lobe of the lateral segment (RLML) was examined. The average RLML of the FL group was 0.45%, which was significantly lower than that of the NFL group (7.11%) (p < 0.0001). CONCLUSIONS: Rats with fatty liver seldom had liver metastases compared to normal rats. This means that fatty liver itself can possibly bring about situations with infrequent liver metastases.

Animals↗