Jmh. Preuss et Rg. Goldie, THE INFLUENCE OF AGE ON ISOLATED TRACHEAL RESPONSIVENESS TO SPASMOGENS, European journal of pharmacology, 345(1), 1998, pp. 71-77
The influence of animal age was examined on the responses of guinea-pi
g (birth-156 weeks) and rat (4-136 weeks) isolated tracheal tissue to
the spasmogens histamine, 5-hydroxytryptamine (5-HT) and potassium ion
s (K+) using functional and biochemical techniques. Over the ages birt
h-12 weeks in the guinea-pig, K+ potency decreased 1.5 fold whereas hi
stamine potency increased 2-fold between the ages of birth-2 weeks and
then declined to original levels by age 20 weeks. 5-HT potency declin
ed over the entire age range examined, resulting in a 25.1 fold decrea
se between the ages of 1 and 156 weeks. In the rat, 5-HT potency remai
ned unchanged and a small but progressive increase in K+ potency was o
bserved with respect to animal age. Significant age-related changes in
inositol phosphate accumulation were observed in both unstimulated an
d histamine-stimulated isolated guinea-pig tracheal smooth muscle whic
h did not correlate with the functional changes observed in response t
o spasmogenic stimulation. The results describe disparate age-related
changes between two species of different spasmogenic agonists with the
majority of age-related changes occurring during the maturation phase
of growth of the guinea-pig. (C) 1998 Elsevier Science B.V.