Arleen Richardson

Biphasic dose-response effect of baclofen on haloperidol catalepsy in the rat

Haloperidol-induced catalepsy in rats is reduced by low dose baclofen and is potentiated by high dose baclofen. This biphasic behavioral effect is consistent with reported differences between presynaptic and postsynaptic GABA receptors. Low dose baclofen could have an anti-cholinergic effect by activating presynaptic GABA receptors that inhibit the release of acetylcholine. High dose baclofen could have an anti-dopamine effect by activating postsynaptic GABA receptors that inhibit the firing of dopamine neurons.

Quantification of Cells in Culture

Cell enumeration using the hemocytometer is applicable when determining the number of cells in a suspension and when the number of samples to be analyzed is relatively small. Hemocytometry is also useful for determining the proportion of singly dispersed cells in a suspension and an estimation of the frequency of viable cells.

Generation of Mouse Astroglia and Microglia Cultures from Mouse Neopallium

Newborn rats or mice are generally used as the source of tissue for glial cultures. Only about 1% of cells survive the cell disaggregation process and culture environment, and neurons that survive die within the first few days of culturing. Terminally differentiated cells, which can no longer divide, are overgrown by the proliferating, immature cells. As a result, the cells in culture are mainly immature cells and therefore cultures are very plastic. How the cultures will develop and which cell types, i.e., astroglia, Oligodendroglia, ependymal cells, or microglia, will enrich the culture, depends on the culture medium and the physical conditions under which the cells are grown. In addition to varying the components of a chemically defined medium or adding or removing serum from the medium, it is possible to add to the cultures growth factors and/or cytokines in pure recombinant form, or as soluble products in medium conditioned by cells, that produce and secrete the factors. (The latter is considerably cheaper). The addition of such factors to cultures can have dramatic effects. It should be noted that such factors may affect more than one cell type and may initiate different effects in different cells. The factors may interact with other factors synergistically, additively, or in an inhibitory way. Moreover, their half-life is short. This subject is extremely complex and beyond the scope of this book.

Procedures for Subculturing Cells

Cells attach to the culture substratum with varying degrees of adherence. Some types of cells do not adhere at all and grow as cell suspensions in the medium. Such cells are referred to as nonadhering cells (nonanchorage-dependent cells). Cells that have to attach to the substratum to proliferate are referred to as adhering cells (anchorage-dependent cells).

Studies of the Binding of Human and Guinea Pig CT to Human and Guinea Pig Lymphocytes

It has been reported that in the absence of antibody, Clq or CI will bind to human T and B lymphocytes, lymphoblastoid cell lines and platelets. Since the binding of Clq is reported to occur independently of both the Fc receptor and membrane surfaces incorporating beta2 microglobulin, the existence on lymphocytes of a specific receptor for Clq has been proposed. As little is known about the Cl¯ binding properties of the proposed receptor or its existence on lymphocyte membranes of other species, the Cl¯ fixation and transfer test was used to investigate the characteristics of human (hu) and guinea pig (gp) Cl¯ binding by hu and gp lymphocytes. At an ionic strength of 0.065 and a temperature of 37d`C, the kinetics of Cl¯ binding and the number of Cl¯ binding sites detected on gp lymphocytes with hu or gp Cl¯ were virtually identical. In contrast significant differences were observed in the number of Cl¯ binding sites detected and in the kinetics of gp and hu Cl¯ binding by hu lymphocytes. These differences...