Speedball (heroin + cocaine) is a prevalent drug combination among intravenous drug users. Although its use is generally discussed to be a function of changes in the rewarding effects of either or both drugs, changes in the aversive effects of either drug may also be impacted (weakened) by the combination. To address this latter possibility and its potential role in the use of speedball, the present studies examined the interaction of cocaine and heroin in taste avoidance conditioning. In Experiment 1, male Sprague-Dawley rats were given access to a novel saccharin solution and then injected with either vehicle or heroin (3.2 mg/kg, IP) followed immediately by various doses of cocaine (10, 18 or 32 mg/kg, SC). At the two lowest doses of cocaine, only animals injected with the drug combination (H + C) displayed a taste avoidance relative to control subjects (taste avoidance was induced with both the combination and the high dose of cocaine). At no dose did animals injected with the combination of heroin and cocaine drink more than animals injected with cocaine alone. In Experiment 2, male Sprague-Dawley rats were similarly treated but injected with vehicle or cocaine (10 mg/kg) followed by injections of various doses of heroin (1.8, 3.2, 5.6 or 10 mg/kg). At the three highest doses of heroin, only animals injected with the drug combination (C + H) displayed significant avoidance relative to control subjects (no avoidance was evident with the combination of cocaine and the low dose of heroin). At no dose did animals injected with the combination of cocaine and heroin drink more than animals injected with heroin alone. Together, these results suggest that the aversive effects of heroin and cocaine are not attenuated by co-administration by cocaine and heroin, respectively. The importance of this for the use of speedball was discussed.

速球（海洛因+可卡因）是静脉吸毒者中普遍使用的药物组合。尽管通常将其用途讨论为改变任一种或两种药物的奖励作用的函数，但联合使用也可能影响（减弱）任一种药物的厌恶作用的改变。为了解决后者的可能性及其在使用速球运动中的潜在作用，本研究研究了可卡因和海洛因在避免味觉调节中的相互作用。在实验1中，雄性Sprague-Dawley大鼠可以使用新型糖精溶液，然后注射媒介物或海洛因（3.2 mg / kg，IP），然后立即注射各种剂量的可卡因（10、18或32 mg / kg， SC）。在两种最低剂量的可卡因下，相对于对照对象，只有注射了药物组合（H + C）的动物才表现出味觉回避（通过组合和高剂量的可卡因均可诱发味觉回避）。没有剂量的海洛因和可卡因组合注射的动物比单独注射可卡因的动物喝更多。在实验2中，对雄性Sprague-Dawley大鼠进行了类似的处理，但注射了媒介物或可卡因（10 mg / kg），然后注射了各种剂量的海洛因（1.8、3.2、5.6或10 mg / kg）。在海洛因的三种最高剂量下，仅注射了该药物组合（C + H）的动物相对于对照对象表现出显着的回避作用（可卡因和低剂量的海洛因组合没有回避作用）。注射可卡因和海洛因组合的动物没有剂量要比单独注射海洛因的动物喝更多。在一起，这些结果表明，可卡因和海洛因分别共同给药并不会减弱海洛因和可卡因的厌恶作用。讨论了使用速球的重要性。