THE EFFECT OF OCTREOTIDE ON BREATHING AND THE VENTILATORY RESPONSE TOCO2 IN CONSCIOUS DOGS

It has been reported that injection of somatostatin into the brain-ste m will lead to apnoea in animals. The aim of this study was to determi ne whether peripheral administration of octreotide, an analogue of som atostatin, could influence the control of breathing, We measured the t idal volume, respiratory rate and ventilatory response to CO2 before a nd after the intravenous injection of two dose levels of octreotide (0 .1 mg and 0.5 mg) or saline in four conscious adult dogs. Injection of octreotide altered the breathing pattern with a mean decrease in the respiratory frequency of 23% (p<0.05) and an increase in the tidal vol ume by 16% (p<0.05), resulting in no net change in ventilation. The no rmal value of the ventilatory response to CO2 ranged between 1.0-3.2 L .min(-1.)mmHg(-1), with a minor variance within each do:: but a signif icant difference amongst the four dogs (p<0,05). No significant change in the ventilatory response to CO2 was observed after octreotide, We conclude that intravenous octreotide alters the pattern of breathing b ut preserves minute ventilation; peripheral administration of octreoti de does not influence the ventilatory response to CO2.