The effect of lead on two calcium sensitive processes was determined. Micromolar concentrations of lead successfully replaced calcium in the activation of calmodulin-sensitive phosphodiesterase and in the promotion of potassium loss from erythrocytes. Both actions of lead were blocked by trifluoperazine--an inhibitor of calmodulin function. We propose that some of the toxic effects of lead may ...

The characteristics of host-guest complexation between cyclodextrins (beta-CD, DM-beta-CD, HP-beta-CD) and protonated (pH 1.9, 6.2) or basic (pH 10.2) forms of trifluoperazine (TF) were investigated by spectrometric method. The association constants of complexes obtained at different temperatures and pH were calculated using Scott's equation and the thermodynamic parameters (deltaH, deltaS and ...

We investigated the effect of trifluoperazine (TFP), a calmodulin antagonist, on the fusion of chick skeletal myoblasts in culture. TFP was found to inhibit myoblast fusion. This effect occurs at concentrations that have been reported to inhibit Ca2+-calmodulin in vitro, and is reversed upon removal of TFP. In addition, other calmodulin antagonists, including chlorpromazine, N-(6-aminohexyl)-5-...

Microcalorimetric titrations of calmodulin with Ca" and trifluoperazine (TFP) at various molar ratios have been carried out at 25 "C and at pH 7.0. Ca2+ binding to calmodulin produces heat ( A H ) in the presence of TFP, while heat is absorbed in the absence of TFP. The total heat produced by Ca2+ binding to all four sites is increased at increasing TFP-to-calmodulin ratios, attaining a plateau...

Patients: 100 people (76% women) aged 65 years or older, living in a residential care facility with probable Alzheimer’s disease (National Institute of Neurological and Communicative diseases and Stroke/Alzheimer’s Disease and Related Disorders Association criteria). Participants had a Clinical Dementia Rating scale (CDR) severity of stage 1 or greater, a Neuropsychiatric Inventory (NPI) score ...