Vasoactive intestinal peptide increases intracellular calcium in astroglia: synergism with alpha-adrenergic receptors.

In type I astrocytes from rat cerebral cortex, vasoactive intestinal peptide (VIP) at concentrations below 1 nM evoked an increase in intracellular calcium ion concentration. This response, however, was observed in only 18% of the astrocytes examined. alpha-Adrenergic stimulation with phenylephrine or norepinephrine also resulted in an intracellular calcium response in these cells and the threshold sensitivity of astrocytes to phenylephrine was vastly different from cell to cell.

Adrenalectomy decreases vasoactive intestinal peptide mRNA levels in the rat suprachiasmatic nucleus.

Vasoactive intestinal peptide (VIP) concentrations were shown to be regulated by adrenal steroids. Therefore, we investigated whether adrenal steroids affect VIP mRNA levels, which would suggest an effect on VIP mRNA expression. Adrenalectomy performed on adult male rats resulted in a significant decrease in VIP mRNA in the hypothalamus (from 10.

A decomposition product of a contaminant implicated in L-tryptophan eosinophilia myalgia syndrome affects spinal cord neuronal cell death and survival through stereospecific, maturation and partly interleukin-1-dependent mechanisms.

The L-tryptophan eosinophilia myalgia syndrome (L-TRP-EMS), an inflammatory syndrome characterized by eosinophilia, myalgias, perimyositis, fasciitis and neuropathies, occurred in epidemic proportions in the United States in the summer and fall of 1989. The neuropathic clinical features in L-TRP EMS are complex and mixed. In the present study, one of the impurities most highly associated with development of L-TRP EMS, 1,1'-ethylidenebis[L-tryptophan] (EBT), and two of its diastereoisomeric breakdown products, were compared for evidence of neurotoxicity in vitro.

HIV envelope protein-induced neuronal damage and retardation of behavioral development in rat neonates.

Cognitive and motor impairment are common symptoms among patients infected with the human immunodeficiency virus (HIV), including children who suffer neurological deficits and are frequently developmentally impaired. The HIV envelope protein, gp120, which has been shown to be toxic to neurons in culture, is shed in abundance by infected cells, and thus may play a significant role in the neuropathology of AIDS. To test this possible mechanism, neonatal rats were injected systemically with purified gp120 and the following consequences were observed: (1) radiolabeled gp120 and toxic fragments thereof were recovered in brain homogenates; (2) dystrophic changes were produced in pyramidal neurons of cerebral cortex; (3) retardation was evident in developmental milestones associated with complex motor behaviors.

VIP-mRNA is increased in hypertensive rats.

Vasoactive intestinal peptide (VIP) is a potent vasodilator. We therefore set out to investigate VIP-gene expression in spontaneous hypertensive rats. By quantitative in situ hybridization histochemistry as well as by RNA blot hybridization experiments we discovered a significant increase in VIP transcripts in the brains of those hypertensive rats.