Pharmacological sympatectomy changes heart's inotropic reaction on serotonin in postnatal ontogenesis of rats
Kirillova, V.V.; Nigmatullina, R.R.
Rossiiskii Fiziologicheskii Zhurnal Imeni I.M. Sechenova 93(10): 1132-1142
2007
ISSN/ISBN: 0869-8139 PMID: 18074787 Document Number: 614925
In the present study, the influence of 0.1 microM, 1.0 microM, 10.0 microM serotonin (5-HT) on inotropic function (contraction force, time to peak force, time to relaxation) of desympathetized rats by guanethidine in postnatal ontogenesis was investigated. 5-HT has a positive inotropic effect on atria (178 %) and ventricles (122%) in 21-day old rats. In 21-day old desympathetized rats, serotonin influence on the atrium was depressed by 49 %, while ventricle contraction did not change. Atria contraction force in 100-day old rats increased by 38 %, while ventricle contraction force was decreased by 5-HT. In the 100-day old desympathetized rats, a significant elevation ofinotropic effect of 5-HT in atria by 91% and ventricles by 51% was revealed. It was shown that injection of guanethidine during three weeks since birth changes reaction on 5-HT in postnatal ontogenesis ofrats. In 21-day old desympathetized rats, 5-HT had a negative inotropic effect in the early period after pharmacological sympatectomy, while in the period of compensation the elevation of the positive inotropic effect of 5-HT occurred. Positive inotropic effect of atria in 100-day old desympathetized rats was twice as high as in control group. Our data suggest that there exists an interaction between adrenergic and 5-HT regulation in postnatal ontogenesis of rats.