Browsing by keyword "Verapamil"

Now showing items 1-3 of 3

    • Ca(2+) entry through store-operated channels in mouse sperm is initiated by egg ZP3 and drives the acrosome reaction
      O'Toole, Christine M. B.; Arnoult, Christophe; Darszon, Alberto; Steinhardt, Richard A.; Florman, Harvey M. (2000-05-04)
      Fertilization occurs after the completion of the sperm acrosome reaction, a secretory event that is triggered during gamete adhesion. ZP3, an egg zona pellucida glycoprotein, produces a sustained increase of the internal Ca(2+) concentration in mouse sperm, leading to acrosome reactions. Here we show that the sustained Ca(2+) concentration increase is due to the persistent activation of a Ca(2+) influx mechanism during the late stages of ZP3 signal transduction. These cells also possess a Ca(2+) store depletion-activated Ca(2+) entry pathway that is open after treatment with thapsigargin. Thapsigargin and ZP3 activate the same Ca(2+) permeation mechanism, as demonstrated by fluorescence quenching experiments and by channel antagonists. These studies show that ZP3 generates a sustained Ca(2+) influx through a store depletion-operated pathway and that this drives the exocytotic acrosome reaction.

    • Management of psychotic, treatment-resistant depression
      Rothschild, Anthony J. (1996-06-01)
      As there are no controlled studies on approaches to patients with treatment-resistant psychotic depression many questions remain to be answered. Those that seem worthy of high priority include (1) the efficacy of novel antipsychotic agents (e.g., clozapine, risperidone) for acute and maintenance treatment; (2) the efficacy of newer antidepressant agents such as the SSRIs and nefazodone plus neuroleptic medications; (3) decision trees to delineate the second and third lines of treatment when the first treatment is ineffective; (4) the comparative efficacy of bilateral versus unilateral ECT; (5) the length of time patients should be maintained on medications (which is of particular importance in the case of neuroleptic agents with their potential to cause tardive dyskinesia); (6) the optimal dose of neuroleptic agent for acute treatment; (7) the optimal length of time for medication trials; (8) the use of antidepressant medications during ECT treatments; (9) the importance of the sequence in which TCAs and neuroleptic agents are administered; (10) the delineation of the clinical characteristics of responders to medication versus ECT treatments; and (11) the role of antiglucocorticoid strategies. The answers to these questions would provide clinicians with important tools to treat patients with psychotic depression, an illness that all too frequently can become treatment-resistant.

    • Third-degree heart block complicating supraclavicular brachial plexus block
      Vyas, Anil; O'Connell, Frank M.; Vacanti, Charles A. (1996-09-01)
      Regional anesthesia is frequently administered to elderly patients and those with known cardiovascular disease in the hope of minimizing the cardiovascular complications associated with general anesthesia. Drug interactions between local anesthetics used in regional techniques and calcium channel blockers have been described. To date, however, potentially life-threatening dysrhythmias associated with brachial plexus blockade using the supraclavicular approach have not been reported. We now describe such a case.