Atropine dose-effect relationship

The extract produced a contraction of the preparation which was rapid both in onset and inactivation (see inset. Fig. 1). The dose-response relationship is shown in Fig. 1. In the presence of atropine (lO M), the effect of 0.3 mg/ml of the extract was depressed by 40.7 6.3% of control (n=4) and for 1 mg/ml the depression was 19.9 7.2% of control (n=4). On the other hand, atropine in the same concentration (lO M) abolished the responses to equieffective doses of acetylcholine (3-10 pM). Furthermore, pretreatment with HC-3 (lO M) depressed the stimulatory actions of the extract, with the effects at the two highest doses being significantly different from control (P<0.05) (Fig. 1). 

Meperidine shows certain relationships to both morphine and atropine in its action. Similar to morphine, it exerts a generalized depression of the CNS but, in ordinary doses, does not affect the cough reflex. Similar to morphine, it induces euphoria, and its continued use leads to tolerance and addiction. However, its euphoric and sedative effects are less than that of morphine addiction due to meperidine is more serious than that due to morphine. Meperidine is an effective analgesic,... 

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