Bronstein D M, Mitteldorf P, Sadeghi M M, Kirby K, Lytle L D
Dev Psychobiol. 1986 Sep;19(5):473-87. doi: 10.1002/dev.420190508.
Maturational changes in visceral nociception were measured in developing or adult rats challenged with hypertonic saline or acetylcholine. Chemically induced abdominal constrictions were absent in rats younger than 7 days of age, regardless of the dose of hypertonic saline or acetylcholine used. Age-related increases in the percent of animals responding, the number of abdominal constrictions emitted per responder, and total response duration occurred in animals 10-20 days of age, until adult-like patterns of responding were attained at the time of weaning. Additional changes in the percent animals responding, as well as in the frequency and total duration of abdominal constriction responses, were also seen in postweanling, but not in preweanling, animals. Five-day-old animals did emit audible vocalizations to the intraperitoneal insertion of a hypodermic needle, however, at a time when these animals failed to show observable responses to the noxious visceral stimuli. Hence, mechanisms mediating pain associated with intraperitoneal needle insertion may be functional during the first postnatal week, at a time when mechanisms mediating visceral pain appear to be immature. These differences may be caused by the differential maturation of sensory, neural, or motoric mechanisms important for hypodermic needle insertion versus visceral nociception.
在内脏伤害感受方面的成熟变化，是在接受高渗盐水或乙酰胆碱刺激的发育中或成年大鼠身上进行测量的。无论使用何种剂量的高渗盐水或乙酰胆碱，7日龄以下的大鼠均未出现化学诱导的腹部收缩。在10至20日龄的动物中，出现了与年龄相关的反应动物百分比增加、每个反应者发出的腹部收缩次数增加以及总反应持续时间增加的情况，直至断奶时达到类似成年动物的反应模式。在断奶后的动物中，也观察到了反应动物百分比以及腹部收缩反应频率和总持续时间的其他变化，但在断奶前的动物中未观察到。然而，5日龄的动物在腹腔内插入皮下注射针时确实发出了可听见的叫声，而此时这些动物对有害的内脏刺激未表现出可观察到的反应。因此，介导与腹腔内注射针相关疼痛的机制可能在出生后的第一周就已发挥作用，而此时介导内脏疼痛的机制似乎尚未成熟。这些差异可能是由对皮下注射针插入与内脏伤害感受至关重要的感觉、神经或运动机制的不同成熟度所导致的。
