摘要
在乌拉坦麻醉的大鼠上，间隔５ｍｉｎ３次静注烟碱１７５μｇ／ｋｇ，首剂烟碱后，动物对其负性心率作用产生急性耐受，但对其降压作用不产生急性耐受。相同条件下，间隔５ｍｉｎ３次静注氨甲酰胆碱１０μｇ／ｋｇ，动物对其负性心率和降压作用均不产生急性耐受。在对烟碱负性心率作用产生急性耐受的大鼠上，静注氨甲酰胆碱５和１０μｇ／ｋｇ，负性心率作用显著增强，但降压作用无显著变化。提示烟碱诱导动物对其负性心率作用产生急性耐受后，Ｍ激动剂负性心率作用显著增强。
In urethane-anaesthctized rats,3 doses of
nicotine 175μg/kg were intravenously adminis-tered at 5min
intervals.After the first dose of nicotine, acute tolerance to
effects of nicotine forproducing bradycardia rather than hypotension
was developed Under the same experimentalconditions,3 doses of
carbachol 10μg / kg were also administered at 5 min interval.Each
dose ofcarbachol could decrease mean blood pressure by 50 % and
decrease heart rate by 60 %.Acutetolerance to effects of carbachol
for producing bradycardia and hypotension was not observed.After the
rats were pretreated with nicotine 175μg / kg iv, potentiation of
effects of carbachol forproducing bradycardia rather than hypotension
was observed.It is reasonable to consider thatthe sensitivity of
cardiac muscarinic receptor to its agonist carbachol for producing
bradycardia isincreased after acute tolerance to nicotine-bradycardia
is developed by nicotine pretreatment,and the desensitization of
nicotinic receptor in vagal parasympathetic ganglion and
medullarycardiovascular center may be involved.
出处
《中国应用生理学杂志》
CAS
CSCD
1995年第4期330-332,共3页
Chinese Journal of Applied Physiology
关键词
烟碱
毒理学
氨甲酰胆碱
心率
血压
nicotine
tolerance
nicotinic receptor
cardiac muscarinic receptor
