The ultrastructure of the dorsal periaqueductal nucleus capillaries of the mesencephalon in the cat was studied under the electron microscope in relation to the hematoencephalic barrier, and its four structural levels: 1. Endothelium; 2. Basal membrane; 3, Pericytes; and 4. Glial prolongations. An analysis was performed of what occurs in these four components (in a non-experimental histophysiol...

Gene regulation is central to the biological processes of differentiation, morphogenesis, and the creation of diversity of cell types. The identification of gene regulatory elements is thus essential for the understanding of the molecular mechanism underlying these processes. Here, we present an integrative approach for the identification and characterization of a cis-element of Dbx1 gene. Dbx1...

NADPH-diaphorase is a useful technique to reveal NO producing neurons at light microscopic level (LM). A modification of the technique using the tetrazolium salt BSPT as substrate, is useful to study the ultrastructure of NO neurons. The aim of this work was to perform a detailed analysis of NADPH-diaphorase reactive neurons in rat mesencephalon both at light and electron microscopic levels. NA...

To study cocaine's toxic effects in vitro, we have used primary mesencephalic and striatal cultures from rat embryonic brain. Treatment with cocaine causes a dramatic increase in DNA fragmentation in both primary cultures. The toxicity induced by cocaine was paralleled with a concomitant decrease in the microtubule associated protein 2 (MAP2) and/or neuronal nucleus protein (NeuN) staining. We ...

Orbital cartilage encircles the eye giving strength and support to the neural retina. It is derived from cranial neural crest cells (NCCs), cells that can generate a number of cell types including neurons, glia, and melanocytes. Uniquely in the head, NCCs also make skeletal derivatives that form the majority of the craniofacial skeleton. Differentiation of NCCs into cartilage requires inductive...

The periaqueductal gray (PAG) of the mesencephalon has been implicated to be involved in the control of micturition. We investigated the micturition-suppressing region in the PAG of the cat. Decerebrated 27 adult cats were used. A microelectrode was inserted stereotaxically into the PAG, and a region was searched where electrical stimulation suppressed isovolumetric bladder contractions. Simult...