Chronic hypoxia in pregnancy affected vascular tone of renal interlobar arteries in the offspring.

Hypoxia during pregnancy could affect development of fetuses as well as cardiovascular systems in the offspring. This study was the first to demonstrate the influence and related mechanisms of prenatal hypoxia (PH) on renal interlobar arteries (RIA) in the 5-month-old male rat offspring. Following chronic hypoxia during pregnancy, phenylephrine induced significantly higher pressor responses and greater vasoconstrictions in the offspring. Nitric oxide mediated vessel relaxation was altered in the RIA. Phenylephrine-stimulated free intracellular calcium was significantly higher in the RIA of the PH group. The activity and expression of L-type calcium channel (Cav1.2), not T-type calcium channel (Cav3.2), was up-regulated. The whole-cell currents of calcium channels and the currents of Cav1.2 were increased compared with the control. In addition, the whole-cell K(+) currents were decreased in the offspring exposed to prenatal hypoxia. Activity of large-conductance Ca(2+)-activated K(+) channels and the expression of MaxiKα was decreased in the PH group. The results provide new information regarding the influence of prenatal hypoxia on the development of the renal vascular system, and possible underlying cellular and ion channel mechanisms involved.

Maternal high-salt diets affected pressor responses and microvasoconstriction via PKC/BK channel signaling pathways in rat offspring.

SCOPE: High-salt (HS) intake is linked to hypertension, and prenatal exposure to maternal HS diets may have long-term impact on cardiovascular systems. The relationship between HS diets and cardiovascular disease has received extensive attention. This study determined pressor responses and microvessel functions in the adult offspring rats exposed to prenatal HS. METHODS AND RESULTS: The offspring of 5-month old as young adults in rats were used. Blood pressure, vascular tone, intracellular Ca(2+), and BK channels in mesenteric arteries were measured in the offspring. Phenylephrine (Phe)-induced pressor responses were significantly higher in the prenatal HS offspring. Vessel tension and intracellular Ca(2+) concentrations associated with Phe-induced pressor responses were increased in the mesenteric arteries of the HS offspring. PKC α- and δ-isoforms were upregulated in mesenteric arteries of the HS offspring. The enhanced Phe-mediated vascular activity was linked to the altered PKC-modulated BK channel functions. CONCLUSION: The results suggested that prenatal exposure to HS altered microvascular activity probably via changes in PKC/BK signaling pathways, which may lead to increased risks of hypertension in the offspring.

Exposure to nicotine during pregnancy and altered learning and memory in the rat offspring.

INTRODUCTION: Prenatal exposure to nicotine can cause many fetal developmental problems. This study determined the influence of nicotine during pregnancy on the development of cognitive behavior in the offspring. METHODS: Nicotine was administered to pregnant rats through implanted osmotic mini-pumps at 6mg/kg/day and flow rate of 60 µl/day for whole pregnancy from gestational day 4. Fetal and offspring body and brain weight was measured. Learning and memory were tested in adult offspring with Morris water maze; Learning and memory-related receptors were measured. RESULTS: The results showed that exposure to prenatal nicotine (PN) not only caused fetal growth restriction, but also had long-term effects on learning and memory in the offspring. The PN offspring exhibited longer escape latency regardless of sex. The number of passing the platform was significantly less in the PN offspring than that of the control. The expression of messenger RNA (mRNA) and protein of N-methyl-D-aspartic acid receptor (NMDAR) in the hippocampus was significantly increased, whereas alpha7 nicotinic acetylcholine receptor (α7 nAChR) protein was decreased with unchanged α7 nAChR mRNA in the PN offspring. CONCLUSION: The data provided novel information on the PN-affected development in learning and memory in the offspring, suggesting that α7 nAChR and NMDAR1 in the hippocampus might be the targets for actions of PN in association with memory impairment.

Hippocampal apoptosis involved in learning deficits in the offspring exposed to maternal high sucrose diets.

The hippocampus plays a crucial role in learning and memory, and neuronal apoptosis in the hippocampus contributes to learning deficits. Metabolism problems in pregnancy related to excessive fuel consumption (e.g., high fat, high sugar) may influence cognitive and behavioral functions in the offspring by affecting developing brain cells. This study determined the influence of maternal high sucrose (HS) diets on behavior and hippocampal neurons in the young offspring. The ratio of brain weight to body weight in the offspring exposed to prenatal HS diets was significantly decreased; the Morris water maze showed that the offspring exposed to prenatal HS diets exhibited increased escape latencies and path length during navigation testing, while there were no changes in time spent in the target quadrant and number of target approaches. In the offspring exposed to prenatal HS, TUNEL-positive cells were significantly increased in CA1, CA2 and CA3 of the hippocampus; protein expression of insulin-like growth factor-I, PI3K and phosphorylated Akt was significantly decreased, while caspase-3 and N-methyl-d-aspartate receptors were significantly increased in the hippocampus, and there was no change in expression of Bcl-2 and Akt. The results demonstrated that prenatal HS diets could induce the spatial acquisition deficits in the young offspring associated with hippocampal apoptosis, and altered signaling factors for antiapoptosis in the hippocampus might play a critical role in cognition disorders in young children.

High-sucrose diets in pregnancy alter angiotensin II-mediated pressor response and microvessel tone via the PKC/Cav1.2 pathway in rat offspring.

This study determines the influence of a prenatal high-sucrose (HS) diet on angiotensin II (Ang II)-mediated pressor response and determine the underlying mechanism. Pregnant rats were provided with a 20% sucrose solution diet throughout gestation. Blood pressure and vascular response to Ang II were measured in 5-month-old adult offspring. Currents of L-type Ca(2+) channels (Cav1.2) were measured in smooth muscle cells of small mesenteric arteries from the offspring. Ang II-mediated pressor response was higher in the offspring exposed to prenatal high sugar compared with the control. In mesenteric arteries from the HS offspring, AT1 receptors (AT1R), not AT2 receptors, mediated the increased vasoconstriction; protein kinase C (PKC) antagonist GF109203X suppressed the Ang II-increased vasoconstriction; PKC agonist phorbol 12,13-dibutyrate produced a greater contractile response that was reversed by the Cav1.2 antagonist nifedipine. The expression of PKCα was increased, whereas PKCδ was unchanged; KCl-induced vasoconstriction was stronger and was suppressed by nifedipine; nifedipine also reduced the enhanced vasoconstriction by Ang II. In addition, the Cav1.2 of smooth muscle cells in mesenteric arteries from the HS offspring showed larger current density, although its expression was unchanged. The data suggest that a HS diet during pregnancy alters Ang II-mediated pressor response and microvessel tone acting through the PKC/Cav1.2 pathway in the offspring that may in part be because of alterations in AT1Rs, PKCα and Cav1.2.

Angiotensin II-mediated vascular changes in aged offspring rats exposed to perinatal nicotine.

This study determined the long-term influence of prenatal nicotine exposure (PN) on blood pressure and vascular functions in the aged offspring rats. PN did not affect body weight and plasma adrenocorticotropic hormone level; however, it significantly reduced plasma angiotensin I and angiotensin II in both sexes. Systolic pressure in the male aged PN offspring was significantly higher. Angiotensin II-increased mean arterial pressure was higher in the aged PN offspring than that in the control regardless of sex. AT1 receptor blocker losartan, not AT2 receptor antagonist PD123319, reduced blood pressure in the aged PN rats more than that in the control. In the aged PN offspring, angiotensin II-increased vessel contraction and intracellular calcium level were higher in small mesenteric arteries. Acetylcholine-mediated vascular relaxation was weaker, and nitric oxide-related endothelial functions were damaged in aortic rings of PN offspring. Thickness of the wall of mesenteric arteries was increased in the male aged PN offspring. Ratio of AT1/AT2 receptors was significantly increased in the vessel of the PN group regardless of sex. These data provide new information on the very long term influence of PN on vascular structures and functions in the aged offspring, demonstrate that the aged PN female rats were not free of vascular risks after menopause, and suggest that multiple pathways may be involved in the detrimental alterations of the cardiovascular system of the PN rats.