Contact sensitivity (CS) to 2,4-dinitrofluorobenzene (DNFB) is maximal 6 d after sensitization but declines rapidly. Previous studies have shown that this rapid decline is due to auto-anti-idiotypic (anti-Id) antibodies produced by the host. The present study was done to investigate the mechanism(s) involved in his down-regulation of the effector phase of the CS reaction. Using transfer of CS t...

GABAB receptor (GABABR)-mediated presynaptic inhibition regulates neurotransmitter release from synaptic terminals. In the neonatal hippocampus, GABABR activation reduces GABA release and terminates spontaneous network discharges called Giant Depolarising Potentials (GDPs). Blocking GABABRs transforms GDPs into longer epileptiform discharges. Thus, GABABR-mediated presynaptic inhibition of GABA...

Parkin is an E3 ubiquitin ligase, mutations in which are responsible for autosomal recessive juvenile parkinsonism. Recently, several structures of Parkin have been solved, revealing its serpentine shape and modes of auto-inhibition.

Introduction: Effects of melatonin (MT) were comparatively examined on melanophores of isolated skin in adults and tadpole’s tailfin of a frog Rana cyanophlyctis. MT is generally considered as a potent melanophores aggregating hormone besides regulating the sleep wake cycle in vertebrates. Methods: Melanophore size index (MSI) was chosen as a recording parameter of the responses. Concentr...

Escherichia coli heat-labile enterotoxin (LT), an oligomeric protein with one A subunit (LTA) and five B subunits, exerts its effects via the ADP-ribosylation of Gsalpha, a guanine nucleotide-binding (G) protein that activates adenylyl cyclase. LTA also ADP-ribosylates simple guanidino compounds (e.g., arginine) and catalyzes its own auto-ADP-ribosylation. All LTA-catalyzed reactions are enhanc...