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烟碱急性给药（２．０，３．５和５．０ｍｇ／ｋｇ，ｉｐ）诱发大鼠体温下降具有剂量依赖性。美加明（１．０和５．０ｍｇ／ｋｇ，ｉｐ）可部分拮抗烟碱的体温下降作用，而六甲溴胺（５ｍｇ／ｋｇ，ｉｐ）不表现拮抗活性。烟碱（２．０，３．５和５．０ｍｇ／ｋｇ，ｉｐ）每日一次，连续１２ｄ给药，随着时间推移，体温下降幅度明显减小。第１３ｄ给予较小剂量烟碱（１．８ｍｇ／ｋｇ，ｉｐ）激发给药，观察到耐受进一步形成，高剂量组（５．０ｍｇ／ｋｇ）几无体温下降出现，低剂量组（２．０ｍｇ／ｋｇ）体温下降明显。激发给药２０ｍｉｍ后取大鼠大脑进行受体结合试验，结果表明各剂量组中枢Ｎ受体密度的增加也具有剂量依赖性。
Acute nicotine administration (2.0, 3.5 and 5.0 mg / kg, ip) induced a dose-dependent decrease in body temperature in rats. Mecamin (1.0 and 5.0 mg / kg, ip) partially antagonized the hypothermic effect of nicotine, whereas hexamethonium bromide (5 mg / kg, ip) did not show antagonistic activity. Nicotine (2.0, 3.5 and 5.0 mg / kg, ip) was administered once daily for 12 consecutive days with a significant decrease in body temperature over time. On the 13th day, the mice were challenged with nicotine (1.8mg / kg, ip) at a lower dose, and further toleration was observed. In the high dose group (5.0mg / kg) 0mg / kg) decreased significantly in body temperature. After stimulated with 20mim, the brains of rats were taken for receptor binding assay. The results showed that the increase of central N receptor density in each dose group was also dose-dependent.