[Establishment of a mouse forestomach carcinoma cell line (MFC) with spontaneous hematogenous metastasis and preliminary study of its biological characteristics]

A mouse forestomach carcinoma cell line (MFC) prone to blood-born metastasis to lung was established in vitro. This cell line has been subcultured for more than 132 passages. MFC cells lacked in contact inhibition and, morphologically, appeared as round, polygonal and spindle cells. Ultrastructurally, there were abundant microvilli on the cellular surface and extensive filopodia in the cytoplasm; nuclei showed irregular shape with an increased nucleus-cytoplasm ratio; desmosomes, hemidesmosomes as well as a small number of tonofibrils were observed. The doubling time of MFC cell population was 24.7 hours. The average mitotic index was 32.9% and the maximum was 62% with 70-76 mode. The homotransplant efficiency was 100% (11/11). In morphology, the solid tumors induced were similar to FC tumor, from which the MFC cell line was derived and 81.8% (9/11) developed spontaneous lung metastasis. It is indicated that this cell line still retains the primary tumor's feature of spontaneous hematogenous metastasis. MFC cell line might be very useful in experimental treatment, study of tumor metastatic mechanism and isolating subpopulation.

[Establishment and biologic properties of a mouse uterine cervix cancer cell line (MUCC) with lymphatic and hematogenous metastatic capacities]

For study of tumor metastatic mechanism, a mouse uterine cervix cancer cell line (MUCC), as derived from a transplantable mouse uterine cervix cancer No. 27 (U 27) with metastatic capacities through lymphatics and blood, was established in vitro. It has been successfully maintained for more than 24 months through more than 100 passages. MUCC cells are epithelioid with definite malignant morphological features. The doubling time of the cell population is 27.8 hours. The average mitotic index is 30.6%, with a maximum of 58.9%. Chromosomes show aberration in number and structure. The homotransplant rate is 75% (9/12). The solid tumor, produced by homotransplant, is similar to the tumor U 27. Metastases are present in the lymph nodes and lungs in these 9 animal models. It is evident that this cell line retains the capacity of inducing daughter tumor lines with spontaneous lymphatic and blood metastases. MUCC cell line might be very useful in isolating subpopulations which possess the different metastatic abilities and the study of metastatic mechanism.

In vivo and in vitro studies on the regulation of cholinergic neurotransmission in striatum, hippocampus and cortex of aged rats

Young (3 months) and senescent (23 months) rats were challenged with oxotremorine both in vivo, to determine its effects on acetylcholine content in hemispheric regions, and in vitro, to assess its action on K+-evoked release of ACh from brain synaptosomes. The drug failed to inhibit KCl-induced [3H]ACh release from the P2 fraction of striatal and hippocampal homogenates of the senescent animals, whereas it was less efficient in increasing striatal ACh content. In contrast, oxotremorine was still able to stimulate an increase in ACh in the hippocampus and cerebral cortex of the aged rats to the same extent as it did in the young ones. The [3H]ACh output from striatal synaptosomes was lower in old rats with respect to young ones at low KCl depolarizing concentrations but was equal in the two groups at a high depolarizing concentration. In the hippocampus of the senescent rats, the release was significantly lower at each concentration of KCl used, resulting in a parallel downward-shift in the concentration-release plot. We also measured cholinergic muscarinic receptor binding in rat hemispheric regions using the radioligand [3H]dexetimide, a classical non-selective muscarinic receptor antagonist. It was found, in conformity with some of the literature, that receptor binding was decreased by about 32% in striatum of aged female rats as compared to younger rats. Changes were not observed in cortex and hippocampus. Analysis of the binding data indicated that the observed decrease in specific ligand binding was due to a decrease in the number of binding sites without a change in affinity. The results favor, once again, the cholinergic hypothesis for geriatric dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro and in vivo evidence for the existence of presynaptic muscarinic cholinergic receptors in the rat hippocampus

The intrahippocampal injection of kainic acid cleared 50% of muscarinic receptors and favored the detection of a further 20% loss in hippocampal presynaptic muscarinic receptors produced by electrolytic lesion of the medial septal nucleus as determined by Scatchard analysis of the saturation isotherms of [3H]dexetimide binding. In accordance, a decrease of about 20% in the in vivo accumulation of [3H]dexetimide in the hippocampus was found in animals lesioned in the medial septal nucleus. This effect occurred at both the dose of 5 micrograms/kg and at the saturating dose of 100 micrograms/kg of [3H]dexetimide. The results suggest that the loss was due to decreased receptor number rather than decreased receptor affinity.

Modifications in recognition sites for neurotransmitters in rat hippocampus by kainic acid lesion

The specific binding of the tritiated radioligands of dexetimide, serotonin, clonidine, prazosin, WB-4101 and dihydroalprenolol to hippocampal membranes was determined two weeks after producing a virtual complete degeneration of perikarya by the local application of 0.5 micrograms of kainic acid in the dorsal and ventral parts of the hippocampus. Afferent terminals were unaffected by the neurotoxin since the contents of noradrenaline, serotonin and acetylcholine, as well as the activity of choline acetyltransferase, were not modified. Scatchard analysis revealed that the kainic acid lesion produced a 60% decrease in the density of both cholinergic muscarinic binding sites and serotonin binding sites. A significant portion of alpha 1- and alpha 2-adrenoceptor binding sites are also associated with intrinsic neurons of the hippocampus, as shown by the approximately 30% reduction in the densities of tritiated WB-4101, prazosin and clonidine produced by the action of kainic acid. By contrast, the affinity and density of beta-adrenoceptor binding sites were unaffected by the lesion. It is suggested that the recognition sites of the different receptor populations surviving the lesion most likely reside on homologous and/or heterologous nerve terminals.