Details

Autor(en) / Beteiligte

• Hissa, Raimo
• John, Mathew T.
• Pilo, Bonny
• Viswanathan, Mohan
• George, John C.

Titel

Noradrenaline-induced hypothermia is suppressed in the vagotomized cold-exposed pigeon

Ist Teil von

• Comparative biochemistry and physiology. A, Comparative physiology, 1995-05, Vol.111 (1), p.89-97

Ort / Verlag

United States: Elsevier B.V

Erscheinungsjahr

1995

Quelle

MEDLINE

Beschreibungen/Notizen

• Vagotomized (VX) pigeons studied 2 days after surgery exhibited a significant decrease in cloacal temperature ( T b) and respiratory rate ( R f), and an increase in heart rate ( H f) and metabolic rate ( M) at the thermoneutral zone, when compared with sham-operated (SVX) pigeons. The effect of intravenous noradrenaline (NA) on T b, R f, H f and M was examined in SVX and VX-pigeons at 15°C. Following NA administration, the T b and R f in the SVX-birds dropped from the preinjection level, but in VX-pigeons, they were not significantly altered. In SVX-pigeons, a total suppression of shivering was apparent following NA-injection, while in the majority of VX-pigeons, shivering was only slightly affected or even increased. The H f in both SVX- and VX-birds increased following NA-injection. The responses to reserpine were qualitatively similar to NA, although much slower. There were no differences between SVX- and VX-birds with regard to T b, M and R f following acetylcholine (ACh) and eserine (Ese) injection. H f increased after ACh + Ese administration in SVX-pigeons, but in VX-birds, it decreased after an initial surge. Shivering was suppressed for 18–20 min in SVX-birds and 30–50 min in VX-birds. It is suggested that the lack of the hypothermic effect of NA in VX-birds is due to the maintenance of oxygen uptake with unimpaired capacity for shivering.