Yu G Z, Kaba H, Saito H, Seto K
Department of Physiology, Kochi Medical School, Japan.
Brain Res Bull. 1993;31(6):701-6. doi: 10.1016/0361-9230(93)90144-z.
The spontaneous firing activity of olfactory bulb mitral cells and their response to intrabulbar infusion of GABAA receptor antagonist bicuculline were studied in ovariectomized, urethane-anesthetized female rats. Mitral cells recorded in the absence of specific stimuli and nasal airflow displayed three distinct patterns of spontaneous firing: high-frequency bursts with relatively long silent periods; high-frequency bursts without accurately defined silent periods; continuous. Infusion of bicuculline (0.2 nmol) into the bulb yielded inconsistent results on spontaneous firing and its inhibition evoked by electrical stimulation of the lateral olfactory tract. Of 32 cells tested, the spontaneous firing rate increased for 24, decreased for 6, and was not altered for 2. Likewise, of 18 cells tested, the poststimulus inhibitory period shortened for 12, lengthened for 4, and not altered for 2. An increased dose (0.4 nmol) of bicuculline produced dose-response relationships simply without any reversal effect. These results suggest that the heterogeneity of mitral cells exists in the context of local interneuronal circuitry in the bulb.
在去卵巢、氨基甲酸乙酯麻醉的雌性大鼠中，研究了嗅球二尖瓣细胞的自发放电活动及其对球内注射GABAA受体拮抗剂荷包牡丹碱的反应。在没有特定刺激和鼻气流的情况下记录的二尖瓣细胞表现出三种不同的自发放电模式：具有相对较长静息期的高频爆发；没有精确界定静息期的高频爆发；连续放电。向嗅球内注射荷包牡丹碱（0.2 nmol）对自发放电及其由外侧嗅束电刺激诱发的抑制产生了不一致的结果。在32个测试细胞中，24个细胞的自发放电率增加，6个细胞的自发放电率降低，2个细胞的自发放电率未改变。同样，在18个测试细胞中，刺激后抑制期缩短的有12个，延长的有4个，未改变的有2个。增加剂量（0.4 nmol）的荷包牡丹碱仅产生剂量反应关系，而没有任何反转效应。这些结果表明，二尖瓣细胞的异质性存在于嗅球局部中间神经元回路的背景中。
