Abstract
In the electrically stimulated guinea-pig ileum, which was incubated in the modified Krebs-Henseleit bicarbonate buffer solution containing various concentrations of electrolytes at $4^{\circ}C$ for 24 hours, the effect of naloxone on the inhibitory action of morphine was investigated. Incubation potentiated the inhibitory action of morphine. In the incubated preperation, the inhibitory action of morphine was potentiated in the $Na^+\;75mM$, and $K^+\;2.9mM$ groups, while that action of morphine was reduced in the $Ca^{++}\;3.6mM,\;Mg^{++}$ free and $Mn{++}\;0.2mM$ groups. Naloxone in incubation media potentiated in the inhibitory action of morphine. In the preparations which were incubated in various concentrations of electrolytes plus naloxone, the action of morphine was reduced in $Na^+\;75mM,\;K^+\;2.9mM$, and $Ca^{++}\;3.6mM$ groups, while that action of morphine was potentiated in $Mg^{++}$free and $Mn{++}\;0.2mM$ groups. Naloxone antagonised those actions of morphine. However, $pA_2$ values for naloxone (index for affinity for antagonist) was not changed. Thus changes in the inhitory action of morphine caused by incubation are probably not the result of changes in the affinity of receptor, but due to the alterations in the events which precede or follow the receptor binding by incubations.
Guinea-pig ileum을 naloxone을 가(加)하거나 가(加)하지 않은 전해질(電解質) 농도(濃度)가 다른 modified Krebs-Henseleit bicarbonate buffer solution에 $4^{\circ}C$에서 24시간 incubation한 다음, morphine의 수축(收縮) 억제작용(抑制作用)으 관찰(觀察)하여 다음과 같은 성적(成績)을 얻었다. 1) Incubation 자체(自體)로써 morphine의 작용(作用) 강화(强化)되었다. 2) Incubation media 내(內) 전해질(電解質) 변동(變動)은 $Na^+\;75mM$ 군(群)과 $K^+2.9mM$ 군(群)에서는 morphine의 작용(作用)이 강화(强化)되었고, $Ca^{++}\;3.6mM$ 군(群), $Mg^{++}$ free 군(群)과 $Mn^{++}\;0.2mM$ 군(群)에서는 약화(弱化)되었다. 3) Incubation media내(內) naloxone은 morphine의 작용(作用)을 강화(强化)하였다. Incubation media 내(內) naloxone을 가(加)하고 전해질(電解質)을 변동(變動)시킨 실험(實驗)에서 $Na^+\;75mM$ 군(群), $K^+2.9mM$ 군(群)과 $Ca^{++}3.6mmM$ 군(群)에서는 naloxone에 의(依)하여 morphine 작용(作用)이 약화(弱化)되었고, $Mg^{++}$ free 군(群)과 $Mn^{++}\;0.2mM$ 군(群)에서는 강화(强化)되었다. 4) Naloxone에 대(對)한 $pA_2$치(値)는 전군(全群)에서 변동(變動)이 없었다. 5) 이상(以上) 실험성적(實驗成績)은 naloxone opiate receptor에 대(對)한 작용외(作用外)에 세포막 또는 근세포수축기구(筋細胞收縮機構)에 영향(影響)을 미처 morphine의 작용(作用)에 영향(影響)을 줄 수 있음을 시사(示唆)한다.