Relaxation of equine tracheal muscle in vitro by different adrenoceptor drugs

Sammanfattning

Strips of tracheal smooth muscle from 12 horses were contracted by carbachol in tissue baths under isometric conditions. This contraction (approximate to 50% of maximum: EC50) was relaxed completely with adrenoceptor drugs. The only exception was clenbuterol, where the degree of relaxation was approximate to 90%. In all horses the EC50-value for isoprenaline (mean 1.6 x 10(-8)M) was less than that for adrenaline (mean 9.6 x 10(-8) M) and noradrenaline (mean 1.8 x 10(-6)M). The potency ratio was 1 < 6 < 110 which indicates that the beta(2)-subtype dominates among the P-adrenoceptors of equine airways. All preparations were also very sensitive to the specific and potent beta(2)-receptor agonists clenbuterol (mean 5.7 x 10(-9)hr) and procaterol (mean 3.6 x 10(-10)M). No differences in EC50-values due to age. sex and breed were observed in this material, The standard deviation of the mean EC50-values seems to be larger for the specific beta(2)-adrenoceptor agonists than for the unspecific. A reason for this could be differences in the pattern of the beta-adrenoceptor population.

Publicerad i

Journal of Veterinary Pharmacology and Therapeutics
1997, volym: 20, nummer: 3, sidor: 216-219
Utgivare: BLACKWELL SCIENCE LTD

SLU författare

• Törneke, Karolina

  • Institutionen för farmakologi och toxikologi, Sveriges lantbruksuniversitet
    

• Ingvast Larsson, Carina

  • Institutionen för farmakologi och toxikologi, Sveriges lantbruksuniversitet
    

• Appelgren, Lars-Erik

  • Institutionen för farmakologi och toxikologi, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Patobiologi

Publikationens identifierare

• DOI: https://doi.org/10.1111/j.1365-2885.1997.tb00098.x

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/97423