Increased hippocampal uptake of tumor necrosis factor alpha and behavioral changes in mice.

Brain trauma may alter the function of the blood-brain barrier (BBB) and affect psychomotor activity. We have shown that the transport system for tumor necrosis factor alpha (TNF alpha) at the BBB undergoes regulatory changes after spinal cord injury. In this study, we show in CD1 mice that mild trauma by weight-drop to the right temporal region specifically increases the uptake of blood-borne TNF alpha.

Physiological and morphological effects of alendronate on rabbit esophageal epithelium.

Alendronate, an aminobisphosphonate, produces as a side effect a topical (pill induced) esophagitis. To gain insight into this phenomenon, we assessed the effects of luminal alendronate on both esophageal epithelial structure and function. Sections of rabbit esophageal epithelium were exposed to luminal alendronate at neutral or acidic pH while mounted in Ussing chambers to monitor transmural electrical potential difference (PD), short-circuit current (I(sc)), and resistance (R).

Ideomotor apraxia in Alzheimer disease and left hemisphere stroke: limb transitive and intransitive movements.

Objective: Ideomotor apraxia was studied in patients with Alzheimer disease (AD) and unilateral left hemispheric damaged (LHD) stroke to determine whether these groups differed.

Background: Given that the neuropathology of AD is bilateral and more diffuse than the localized involvement in patients after an LHD stroke, and given that the cognitive deficits in AD are more widespread than in LHD stroke, the authors predicted that patients with these disorders would differ in response to an auditory command task administered to evaluate ideomotor apraxia, and that the two patient groups would be significantly more impaired than healthy matched control subjects.

Methods: Twenty-one persons were studied, including equal numbers of patients with AD, patients with unilateral LHD stroke, and control subjects.

Mechanisms of basolateral Na+ transport in rabbit esophageal epithelial cells.

We examined the mechanisms of cellular Na+ transport, both Cl- dependent and Cl- independent, in the mammalian esophageal epithelium. Rabbit esophageal epithelium was dissected from its muscular layers and mounted in a modified Ussing chamber for impalement with ion-selective microelectrodes. In bicarbonate Ringer, transepithelial potential difference was -14.

Opiate tolerance and dependence: receptors, G-proteins, and antiopiates.

Despite the existence of a large body of information on the subject, the mechanisms of opiate tolerance and dependence are not yet fully understood. Although the traditional mechanisms of receptor down-regulation and desensitization seem to play a role, they cannot entirely explain the phenomena of tolerance and dependence. Therefore, other mechanisms, such as the presence of antiopiate systems and the coupling of opiate receptors to alternative G-proteins, should be considered.

Differential effects of endomorphin-1, endomorphin-2, and Tyr-W-MIF-1 on activation of G-proteins in SH-SY5Y human neuroblastoma membranes.

Endomorphin-1 (Tyr-Pro-Trp-Phe-NH2) and endomorphin-2 (Tyr-Pro-Phe-Phe-NH2), peptides recently isolated from bovine and human brain, have high affinity and selectivity for mu opiate receptors. They share sequence similarity with the endogenous opiate-modulating peptide Tyr-W-MIF-1 (Tyr-Pro-Trp-Gly-NH2). The efficacies of these endogenous peptides and of the enkephalin analog DAMGO were compared by measuring their effects on the binding of guanosine-5'-O-(-gamma-[35S]thio)triphosphate ([35S]GTPgammaS) to G-proteins in membranes from SH-SYSY human neuroblastoma cells.

Tyr-W-MIF-1 attenuates down-regulation of opiate receptors in SH-SY5Y human neuroblastoma cells.

Down-regulation of opiate receptors is demonstrated more easily in vitro than in vivo. The possible role of endogenous opiate-modulating peptides in preventing such down-regulation was investigated by addition of Tyr-W-MIF-1 to an in vitro preparation, the human neuroblastoma cell line SH-SY5Y, in which down-regulation of opiate receptors has been demonstrated previously. Although both morphine and Met-enkephalin down-regulated mu and delta receptors after chronic (24 h) exposure in serum-free medium, Tyr-W-MIF-1, at doses of up to 100 microM, did not affect receptor number when administered alone.

Metabolic support of collecting duct transport.

The present studies address the metabolic processes that support the reabsorption of sodium and the secretion of bicarbonate in the interspersed but distinct principal and intercalated cells of the cortical collecting duct (CCD). In microperfused rabbit CCD, sodium reabsorption was measured by lumen-to-bath 22Na flux, and bicarbonate transport was assayed by microcalorimetry. Flux measurements were made before and after metabolic substrate changes or application of metabolic inhibitors.

Receptor-mediated endocytosis of immunoglobulin light chains by renal proximal tubule cells.

We examined the binding, endocytosis, and degradation of immunoglobulin light chains by primary cultures from rat renal kidneys and immortalized human proximal tubule cells. Both the association and dissociation of light chain were rapid and plateaued within 30 min at 4 degrees C. Up to 10(-3) M bovine serum albumin did not inhibit light chain binding to cells.