Physiological responses of vagotomized pigeons exposed to ambient temperatures gradually reduced from 34 degrees C to 2 degrees C.
In pigeons subjected to bilateral cervical vagotomy and sham-vagotomy, measurements of heart rate, breathing frequency, cloacal temperature (Tc), foot temperature (Tf), shivering and metabolic heat production (M) were made during gradual ambient cooling from 34 to 2 degrees C on Day 2 as well as on Day 3 post-surgery. Severe tachycardia was observed in both Day 2 and Day 3 vagotomized (VX) pigeons. Lowering of ambient temperature (Ta) below 28 degrees C produced increased heart rate in both Day 2 as well as Day 3 sham-vagotomized (SVX) and VX pigeons, except with Day 3 VX pigeons exposed to Ta below 12 degrees C when a reversal of the trend became apparent. Breathing frequency in VX pigeons was lower than that in SVX on both days tested, the difference being greater on Day 2 than on Day 3. On both days, the difference in breathing frequency between VX and SVX pigeons was minimal at Ta 30 degrees C and became increasingly greater with Ta above or below this point. Tc dropped significantly in both VX and SVX pigeons in response to ambient cooling on Days 2 and 3. The Day 2 VX pigeons in general had a lower Tc than that in SVX and as Ta continued to drop below 28 degrees C, Tc in VX pigeons dropped more rapidly than in SVX, showing the maximal difference in Tc between the two at Ta 2 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D001833:Body Temperature Regulation; D010856:Columbidae; D006339:Heart Rate; D008297:Male; D012119:Respiration; D012768:Shivering; D013696:Temperature; D014628:Vagotomy