Department of Surgery and Gastrointestinal Research Unit, Mayo Clinic, Rochester, Minnesota 55905, USA.
Auton Neurosci. 2009 Dec 3;151(2):127-34. doi: 10.1016/j.autneu.2009.08.004. Epub 2009 Sep 5.
Age-related changes in non-adrenergic, non-cholinergic (NANC) neurotransmission might contribute to differences in gastrointestinal motility. Our aim was to determine age-related changes in functional innervation with vasoactive intestinal polypeptide (VIP) and substance P (Sub P) in rat jejunum. We hypothesized that maturation causes changes in neurotransmission with these two neuropeptides. Longitudinal and circular jejunal muscle strips from young (3 months) and middle-aged (15 months) rats (total: 24 rats) were studied; the response to exogenous VIP and Sub P and the effect of their endogenous release from the enteric nervous system during electrical field stimulation (EFS) were evaluated. In longitudinal muscle, response to exogenous VIP and endogenously released VIP during EFS were increased in middle-aged rats, while the effect of endogenously released Sub P was decreased. In the circular muscle, the response to endogenously released VIP was increased in middle-aged rats, while the effects of exogenous VIP and endogenously released Sub P were unchanged. Response to exogenous Sub P was unaffected by maturation in both muscle layers. Spontaneous contractile activity was increased in the longitudinal and circular muscle of the older rats. In the jejunum of middle-aged rats, participation of VIP in functional NANC innervation was increased, while functional innervation with Sub P was decreased. These changes in the balance of inhibitory and excitatory neurotransmission occur during the year of maturation in rats and demonstrate an age-dependant plasticity of neuromuscular bowel function.
年龄相关的非肾上腺素能、非胆碱能（NANC）神经递质变化可能导致胃肠道动力的差异。我们的目的是确定血管活性肠肽（VIP）和 P 物质（Sub P）在大鼠空肠中的功能神经支配的年龄相关性变化。我们假设成熟会导致这两种神经肽的神经传递发生变化。来自年轻（3 个月）和中年（15 个月）大鼠的纵向和环形空肠肌条（共 24 只大鼠）进行了研究；评估了对外源 VIP 和 Sub P 的反应以及电刺激（EFS）期间其内源性释放对神经传递的影响。在纵向肌中，中年大鼠 EFS 期间内源性 VIP 释放的反应增强，而内源性 Sub P 释放的作用减弱。在环形肌中，中年大鼠内源性 VIP 释放的反应增强，而外源性 VIP 和内源性 Sub P 释放的作用不变。在两种肌肉层中，外源 Sub P 的反应不受成熟的影响。老年大鼠的纵向和环形肌自发性收缩活动增加。在中年大鼠的空肠中，VIP 参与功能性 NANC 神经支配的增加，而 Sub P 的功能性神经支配减少。这种抑制性和兴奋性神经传递平衡的变化发生在大鼠成熟的一年中，证明了肠神经系统功能的年龄依赖性可塑性。
