John W. Watson

Broad spectrum antiemetic effects of CP-122,721, a tachykinin NK1 receptor antagonist, in ferrets

The potent, selective, tachykinin NK1 receptor antagonist, CP-122,721 ([(+)-(2S,3S)-3-(2-methoxy-5-trifluoromethoxybenzyl)amino-2- phenylpiperidine]), at 0.01-1 mg/kg, s.c. reduced retching and vomiting elicited by loperamide, copper sulfate, ipecac syrup and cisplatin in a dose-dependent manner. ID50 values after subcutaneous administration ranged from 0.02 mg/kg (loperamide) to 0.08 mg/kg (ipecac). Oral CP-122,721 reduced cisplatin-induced emesis with an ID50 of approximately 0.08 mg/kg. The less active (2R, 3R)-enantiomer, CP-132.687, did not significantly suppress retching or vomiting induced by any of the emetogens. These data support the hypothesis that CP-122,721 blocks emesis by a specific action at tachykinin NK1 receptors. Its broad spectrum of antiemetic activity suggests a central site of action.

The effect of 5-lipoxygenase inhibition on Ascaris antigen (Ag)-induced responses in atopic monkeys

The effects of two 5-lipoxygenase (5LO) inhibitors, ZD2138 or Zileuton, on acute, inflammatory responses to aerosolizedAscaris suum (Ag) were determined in atopicMacaca fascicularis monkeys. Monkeys (n=6 each group) were dosed with vehicle, 3 or 10 mg/kg ZD2138, or 30 mg/kg Zileuton (p.o.). Both ZD2138 or Zileuton significantly inhibited ex vivo LTB4 production in Ca2+ ionophore-stimulated whole blood from these same monkeys (n=6 each group) by 45.5% (3 mg/kg ZD2138), 82.5% (10 mg/kg ZD2138) and 84.3% (30 mg/kg Zileuton). ZD2138 (10 mg/kg) reduced bronchoalveolar lavage (BAL) LTE4 levels (65.1% inhibition), BAL neutrophils (88.9% inhibition), and IL-6 (54.0% inhibition) 4h post Ag. Zileuton inhibited these responses and also reduced BAL levels of IL-8 (73.4% inhibition). A second study was performed to evaluate the effects of ZD2138 on chronic Ag-induced responses. Treatment with ZD2138 did not prevent pulmonary inflammation or the development of airway hyperresponsiveness (AHR). Based upon these results, 5LO inhibition significantly reduced ex vivo LTB4 and in vivo LTE4 production as well as several acute inflammatory responses to Ag in the lung. However, ZD2138 did not inhibit more chronic responses following multiple Ag exposure.

N-carbamoyl analogs of zafirlukast: Potent receptor antagonists of leukotriene D4

Exploration of the indole nitrogen region of Zafirlukast (1) has uncovered a potent series of cysteinyl leukotriene D4 (LTD4) antagonists. These studies showed that a variety of functionality could be incorporated in this region of the molecule without sacrificing potency. Efforts to exploit this site in order to improve oral efficacy are discussed.

Primate Models of Asthma

The use of animal models to mimic certain aspect of human disease has proven to be invaluable to biomedical research. Animal models allow experimentation that would be hazardous in humans [1, 2], provide tissue for study in vitro, enable validation of data in a variety of systems, allow genetic and environmental influences to be manipulated or controlled, and facilitate the preclinical assessment of drug efficacy [2].