Nicotinic acetylcholine receptors (nAChR) of the TE671 cell line were investigated using whole-cell and membrane patch recording techniques. At negative holding potentials (VH), pulses of acetylcholine (ACh) elicited whole-cell inward currents that rapidly desensitized. The EC50 value for ACh at VH = -60 mV was 7.8 microM. The ACh-induced current reversed at approximately 0 mV. Desensitization ...

In order to investigate the seasonal changes and the possible role of the free polyamines in the leaves and stems on the alternate bearing habit of the ‘Kinnow’ mandarin (Citrus reticulata Blanco) trees, a comparative study was conducted to analyze the levels of free polyamines  (putrescine, spermidine and spermine) in the leaves and stems tissues of “on” and &ldquo...

Spermine is a substrate of lentil (Lens culinaris) seedling amine oxidase and the oxidation products are reversible inactivators of the enzyme. The spermine is oxidized at the terminal amino groups to a dialdehyde: 2 moles of hydrogen peroxide and 2 moles of ammonia per mole of spermine are formed. The pH optimum of the enzyme with spermine is 7.9 in TI-HCI buffer; the K(m) value is 4.4.10(-4) ...

in this research, we studied polyamines including putrescine (put), spermidine (spd) and spermine (spm) changes in three common bean (phaseolus vulgaris) genotypes, k-s-31167, ge-288 and naz under drought stress. our result showed steadily increase in putrescine (put) and spermine (spm) in all three genotypes.  ge-288 genotype showed decrease and then increasing in spermidine (spd) content but ...

The transmembrane and pore-forming regions of N-methyl-D-aspartate receptors containing the NR1 and NR2B subunits were studied by measuring the effects of various NR1 and NR2B mutants on stimulation and block by spermine. Block by spermine was predominantly affected by mutations in the M3 segment of NR1 and especially in the M1 and M3 segments of NR2B. These regions are in the outer vestibule o...

1. A dual effect of the polyamine spermine on Ca2+ uptake by isolated rat liver, brain and heart mitochondria could be demonstrated by using a high-resolution system for studying mitochondrial Ca2+ transport. Depending on the experimental situation, spermine had an inhibiting or accelerating effects on mitochondrial Ca(2+)-uptake rate, but invariably increased the mitochondrial Ca2+ accumulatio...

Polyamines such as spermine are thought to be endogenous regulators of NMDA (N-methyl-D-aspartate)-type glutamate receptors. Polyamine block of NMDA receptors was studied in excised outside-out patches from rat hippocampal neurons and Xenopus oocytes expressing recombinant receptors. Extracellular spermine and arcaine reduced NMDA single-channel conductance in a voltage-dependent manner, with p...

The polyamines, relatively low-molecular-weight aliphatic compounds, are the main inducers of eukaryotic cell growth and proliferation. Although polyamine requirements for cell growth are well defined, their role is still enigmatic. We have previously reported that amyloid beta-peptide (A beta), the main constituent of senile plaques in Alzheimer's disease (AD) brain, is toxic to neurons throug...

protein aggregation is a serious problem for both biotechnology and cell biology. diseases such as prion misfolding, alzheimer’s, and other amyloidosis are phenomena for which protein aggregation in our living cells is of considerable relevance. human lysozyme has been shown to form amyloid fibrils in individuals suffering from nonneuropathic systemic amyloidosis, all of which have point mutati...