John E. Maggio

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We have previously demonstrated that the venom of the scorpion Leiurus quinquestriatus blocks small-conductance Cl- channels, derived from epithelial cells, when applied to the cytoplasmic surface. We have now purified to near homogeneity, and characterized, the component responsible for this blocking activity. It is a small basic peptide of 4,070 Da. The(More)
Light microscopic studies have demonstrated significant mismatches in the location of neuropeptides and their respective binding sites in the central nervous system. In the present study we used an antiserum raised against a synthetic peptide corresponding to the carboxyl-terminal tail of the substance P (SP) receptor (SPR) to further explore the(More)
In vivo somatosensory stimuli evoked the release of substance P from primary afferent neurons that terminate in the spinal cord and stimulated endocytosis of substance P receptors in rat spinal cord neurons. The distal dendrites that showed substance P receptor internalization underwent morphological reorganization, changing from a tubular structure to one(More)
Studies on cultured cells have shown that agonists induce several types of G protein-coupled receptors to undergo internalization. We have investigated this phenomenon in rat striatum, using substance P (SP)-induced internalization of the SP receptor (SPR) as our model system. Within 1 min of a unilateral striatal injection of SP in the anesthetized rat,(More)
To determine the stability of beta-amyloid peptide (Abeta) and the glial and neuronal changes induced by Abeta in the CNS in vivo, we made single injections of fibrillar Abeta (fAbeta), soluble Abeta (sAbeta), or vehicle into the rat striatum. Injected fAbeta is stable in vivo for at least 30 d after injection, whereas sAbeta is primarily cleared within 1(More)
Substance P (SP) is a putative neurotransmitter in both the peripheral and central nervous systems. In the present report we have used a modification of the Young and Kuhar technique to investigate some of the SP receptors binding properties and the distribution of SP receptors in rat brain. Tritiated SP [( 3H]SP) absorbed extensively to glass but this(More)
The amyloid beta-peptide (Abeta) is the major constituent of neuritic plaques in Alzheimer's disease and occurs as a soluble 40-42-residue peptide in cerebrospinal fluid and blood of both normal and AD subjects. It is unclear whether Abeta, once it is secreted by cells, remains free in biological fluids or is associated with other proteins and thus(More)
The self-assembly of the soluble peptide Abeta into Alzheimer's disease amyloid is believed to involve a conformational change. Hence the solution conformation of Abeta is of significant interest. In contrast to studies in other solvents, in water Abeta is collapsed into a compact series of loops, strands, and turns and has no alpha-helical or beta-sheet(More)
Although there is considerable evidence that primary afferent-derived substance P contributes to the transmission of nociceptive messages at the spinal cord level, the population of neurons that expresses the substance P receptor, and thus are likely to respond to substance P, has not been completely characterized. To address this question, we used an(More)
Beta amyloid protein (A beta) is the major extracellular component of Alzheimer's disease (AD) plaques. In the current study, A beta (1-42) was aggregated in vitro using a method which produces A beta aggregates similar to those found in the AD brain. Twelve male Sprague-Dawley rats were trained in two-lever operant chambers under an alternating lever(More)