Simson P E, Weiss J M
Department of Psychiatry, Duke University Medical Center, Durham, NC 27710.
Brain Res. 1989 Jun 26;490(2):236-42. doi: 10.1016/0006-8993(89)90241-2.
To determine whether benzodiazepine receptors in the locus coeruleus (LC) regulate the firing of LC neurons, the effects of systemic, intracerebroventricular, and local administration of various benzodiazepines on LC activity were compared. Systemic administration of diazepam, chlordiazepoxide, and alprazolam in anesthetized rats markedly attenuated sensory-evoked activity of LC neurons while also suppressing, but to a lesser degree, spontaneous LC firing rates. When microinfused into the LC region, diazepam, chlordiazepoxide, and alprazolam reduced spontaneous LC firing rates to the same extent observed following systemic administration; however, unlike systemic administration, infusion of benzodiazepines into the LC failed to attenuate evoked LC activity. Similarly, intracerebroventricular administration of diazepam and chlordiazepoxide suppressed spontaneous, but not evoked, LC activity. These findings indicate that benzodiazepines suppress spontaneous LC firing by stimulating benzodiazepine receptors in the LC while attenuating evoked LC activity by stimulating benzodiazepine receptors that are neither in the LC nor accessible to benzodiazepines introduced into the ventricular system.
为了确定蓝斑（LC）中的苯二氮䓬受体是否调节LC神经元的放电，比较了全身、脑室内和局部给予各种苯二氮䓬对LC活动的影响。在麻醉大鼠中全身给予地西泮、氯氮䓬和阿普唑仑显著减弱了LC神经元的感觉诱发性活动，同时也抑制了，但程度较轻，LC的自发放电率。当微量注入LC区域时，地西泮、氯氮䓬和阿普唑仑将LC自发放电率降低到与全身给药后观察到的相同程度；然而，与全身给药不同，将苯二氮䓬注入LC未能减弱诱发的LC活动。同样，脑室内给予地西泮和氯氮䓬抑制了LC的自发活动，但未抑制诱发活动。这些发现表明，苯二氮䓬通过刺激LC中的苯二氮䓬受体抑制LC自发放电，同时通过刺激既不在LC中也不能被引入脑室系统的苯二氮䓬所作用的苯二氮䓬受体来减弱诱发的LC活动。
