Kania B F, Lewicki S
Experimental and Clinical Physio-Pharmacological Laboratory, Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 159, 02-787 Warsaw, Poland.
Pol J Vet Sci. 2007;10(4):263-9.
The aim of this study was to determine the influence of nifedypine--competitive antagonist of voltage-gated dependent L-type Ca2+ channels (VGCCs)--on inhibition of reticulo-ruminal motility, heart beats, respiratory rates and other nociceptive behavior symptoms caused by duodenal distention (DD). The animals, which were under general anesthesia, had duodenal and ruminal fistulas and intracerebroventriculary (i.c.v.) cannulas inserted into the lateral ventricle. Reticulo-ruminal contractions were recorded mechanographically using an electronic tensometer. The frequency of reticulo-ruminal contractions was determined by the number of mechanograms with 5 min intervals prior to and after DD (for 180 min). The duodenal distention was performed using a rubber balloon (10 cm length), which was inserted via the duodenal fistula and filled with 40 ml water. Five min DD caused immediate and almost complete inhibition of reticulo-ruminal contractions, nociceptive behavior symptoms, tachycardia and hyperventilation. Nifedypine per se did not change the reticulo-ruminal motility, general behavior or clinical symptoms; however, doses of 1 and 2 mg of nifedypine in toto infused i.c.v 10 minutes before DD prevented all signs of reticulo-ruminal disorders, as well as the general nociceptive behavior. Nifedypine inhibited particularly clinical symptoms such as tachycardia and hyperventilation. The observed antinociceptive action of VGCCs type-L blockers suggests that these channels play a crucial role in the modulation of acute visceral hyperalgesia. Nifedipine can be useful in controlling acute visceral pain associated, for example, with different kinds of colic.
本研究的目的是确定硝苯地平（电压门控依赖性L型钙通道（VGCCs）的竞争性拮抗剂）对十二指肠扩张（DD）引起的瘤胃网胃运动抑制、心跳、呼吸频率及其他伤害性行为症状的影响。处于全身麻醉状态的动物，已插入十二指肠和瘤胃瘘管以及侧脑室脑室内（i.c.v.）插管。使用电子张力计以机械记录法记录瘤胃网胃收缩情况。通过在DD之前和之后（持续180分钟）每隔5分钟的机械图数量来确定瘤胃网胃收缩频率。使用一个橡胶气球（长10厘米）进行十二指肠扩张，该气球通过十二指肠瘘插入并注入40毫升水。5分钟的十二指肠扩张立即且几乎完全抑制了瘤胃网胃收缩、伤害性行为症状、心动过速和通气过度。硝苯地平本身并未改变瘤胃网胃运动、一般行为或临床症状；然而，在DD前10分钟经脑室内注入总量为1毫克和2毫克的硝苯地平可预防瘤胃网胃紊乱的所有迹象以及一般伤害性行为。硝苯地平尤其抑制了心动过速和通气过度等临床症状。观察到的L型VGCCs阻滞剂的抗伤害作用表明，这些通道在急性内脏痛觉过敏的调节中起关键作用。硝苯地平可用于控制例如与不同类型绞痛相关的急性内脏疼痛。
