Reduced normogastric electrical activity associated with emesis: A telemetric study in ferrets

AIM: To characterize the gastric myoelectric activity (GMA) and intra-abdominal pressure changes induced by emetic stimuli (apomorphine and cisplatin) in the ferret.METHODS: GMA and intra-abdominal pressure were recorded in conscious, unrestrained ferrets surgically implanted with radiotelemetry transmitters. Animals were challenged with apomorphine (0.25 mg/kg sc ) and cisplatin (10 mg/kg ip), and the emetic response was quantified via direct observation and intra-abdominal pressure recording for 1 and 4 h, respectively. The GMA was analyzed by spectral analysis; the parameters used to characterize the GMA were the dominant frequency (DF) and the repartition of spectral power in the bradygastric, normogastric and tachygastric frequency anges.RESULTS: Retches were identified on the intraabdominal pressure trace as peaks 0.30 ± 1.01 s in duration and 59.57 ± 2.74 mmHg in amplitude, vomit peaks were longer (0.82 ± 0.06 s, P < 0.01)="" and="" reached="" a="" higher="" pressure="" (87.73="" ±="" 8.12="" mmhg,="" p="">< 0.001).="" the="" number="" of="" retches="" and="" vomits="" quantified="" via="" direct="" observation="" [apomorphine:="" 65.5="" ±="" 11.8="" retches="" +="" vomits="" (r+v),="" cisplatin:="" 202.6="" ±="" 64.1="" r+v]="" and="" intra-abdominal="" pressure="" (apomorphine:="" 68.3="" ±="" 13.7="" r+v,="" n="8;" cisplatin:="" 219.0="" ±="" 69.2="" r+v,="" n="8)" were="" correlated="" (r="0.97," p="">< 0.0001)="" and="" the="" timing="" of="" emesis="" was="" consistent="" between="" the="" 2="" methods.="" apomorphine="" induced="" a="" decrease="" in="" normogastria="" from="" 45.48%="" ±="" 4.35%="" to="" 36.70="" ±="" 4.34%="" (n="8," p="">< 0.05)="" but="" the="" df="" of="" the="" slow="" waves="" was="" not="" changed="" [8.95="" ±="" 0.25="" counts/min="" (cpm)="" vs="" 8.68="" ±="" 0.35="" cpm,="" n="8," p=""> 0.05]. Cisplatin induced a decrease in normogastria from 55.83% ± 4.30% to 29.22% ± 5.16% and an increase in bradygastria from 14.28% ± 2.32% to 31.19% ± 8.33% (n = 8, P < 0.001)="" but="" the="" df="" (9.14="" ±="" 0.13="" cpm)="" remained="" unchanged="" (p=""> 0.05). The GMA changes induced by cisplatin preceded the emetic response as normogastria was reduced for 1 h before the onset of emesis (57.61% ± 5.66% to 39.91% ± 5.74%, n = 6,P < 0.05).="" peri-emesis="" analysis="" revealed="" that="" the="" gma="" was="" significantly="" disturbed="" during="" and="" immediately="" after,="" but="" not="" immediately="" before,="" the="" emetic="" episodes.conclusion:="" the="" induction="" of="" emesis="" is="" reliably="" associated="" with="" a="" disrupted="" gma,="" but="" changes="" may="" also="" occur="" prior="" to="" and="" following="" the="" emetic="" response.="">