Impact On Metabolism Of Water And Sodium And RAS Receptors In Generation By The Exposure Of Nicotine During Perinatal Period

Objective To observe the influence of the metabolism of water and electrolytes and the regulation of renin-angiotensin-system (RAS) in the offspring whose maternal rats were exposed to the stimulation of nicotine via subcutaneous administration during different gestational period.Methods 1. To detect the fetal (21 gestational day) body and brain weight under the condition of which the maternal rats were treated by the nicotine (subcutaneous injection in the dose of 3mg/kg/day) in different gestational period [gestation period (G) or gestation add lactation period (G+L)]. 2. To insight into the changes of the plasma Na +, K + concentration and plasma osmolality, and the behavior of water intake and salt appetite consequented to some simuli (e.g. 24h dehydration and subcutaneous injection of hypertonic saline), in the nicotine adult offspring (i.e. those who were suffered in the exposure of nicotine during preinatal period as mentioned above). 3. To quantitatively analysis the expression of the two angiotensin receptor subtypes (AT₁ and AT₂) in both the forebrain and hindbrain of the nicotine adult offspring with the mothod of Western-blotting.Result 1. Both the body and brain weight of the fetus with the maternal exposure of nicotine in different timing of the perinatal period (i.e. (G) and (G+L)) decreased significantly compared with those in the control. 2. The plasma Na⁺, K⁺ concentration, plasma osmolality, and the spontaneous intake of either water or salt were no difference between the nicotine and control adult offspring. Followed by the stimulus of 24h water deprivation, the salt appetite in the nicotine offspring was obviously elevated, in addition, there was some gender difference in the behavior of the water intake: the female nicotine adult offspring uptook markedly less water in the first 2h rehydration, however, the male exhibited no difference compared with that of control. Given the subcutaneous injection of hypertonic saline, in general, the sodium appetite in the nicotine adult offspring was less than that in the control; the water intake was significantly more than that of control during the preceeding 2h period after the stimulus, nonetheless, the amount in 24h was strongly decreased in the nicotine adult offspring. There also appeared some gender difference, which showed almost a revert situation, in the behavior of water intake under the simulus of subcutaneous injection of hypertonic saline: the male nicotine adult offspring intook less water during the first 2h following the stimulus, nevertheless, the female represented no difference. 3. In female nicotine adult offspring, AT₁ receptor protein in both forebrain and hindbrain was decreased significantly, and AT₂ receptor protein was also declined in the forebrain, compared with those in the control.Conclusion : The exposure of nicotine during perinatal period could result in fetal growth retardation (i.e. in utero growth retardation), and might give rise to the imprinting impact on the regulation of RAS and the metabolism of water and electrolytes. Perinatal maternal exposure to nicotine can lead to fetal growth restriction and offspring water and salt metabolism and control system RAS-prints generated effects.