Basic Research for the role and mechanism of histamine in visual procession

用放射自显影技术研究了单眼摘除和单眼剥夺后大鼠脑内组胺受体的变化。视觉剥夺上丘H3受体的结合。单侧眼球摘除后5、15、30和45天，对侧眼的平均光密度均显著增加。持续注射(S)-α-氟烟组氨酸。L-组氨酸脱羧酶的特异性抑制剂和局部注射喹啉酸可减弱单侧SC去核的作用。在幼年大鼠中，视觉剥夺的上丘H3受体结合量在单侧摘除后显著增加。但单眼剥夺对受体结合无影响。单眼摘除和单眼剥夺后，SC的H1和H2受体结合无明显变化。H3受体结合反应增强的对侧SC[35&gt；S]GTPγS结合反应显著增强。H_3选择性拮抗剂逆转[35&lt；35&gt；S]GTPγS信号增强，而H_1和H_2受体拮抗剂无效。这些结果表明，视网膜分化诱导组胺H3受体结合部位增加，可能是通过选择性地调节组胺神经元对单侧去核的反应，失神经引起的尖端调节的H3受体与G蛋白偶联。

We investigated the changes of histamine receptors in the brains of rats after unilateral enucleation and monocular deprivation using quantitative autoradiography. The H3 receptor binding in the visually deprived superior colliculus (SO. Contralateral to the enucleated eye, was significantly increased 5, 15, 30 and 45 days after unilateral cnuclcation. Continuous injection of (S)-alpha-fluoronielhylhistidine. A specific inhibitor of l.-hislidine decarboxylase, and local injection of quinolinic acid attenuated the effect of unilateral enucleation in the SC. In infant rats, the H3 receptor binding in the visually deprived superior colliculus was significant!} increased after unilateral enucleation. Hut there were no effects of monocular deprivation on the receptor bindings. No significant changes in H1 and H2 receptor bindings were observed in the SC after unilateral enucleation and monocular deprivation. The [^<35>S]GTPγS-binding response was significantly increased in the contralateral SC in which H3 receptor binding response was enhanced. The increased [^<35>S]GTPγS signal was reversed with H_3-selective antagonists, whereas specific H_1 and H_2 antagonists were proved ineffective.These results suggest that retinal differentiation induced an increase in histamine H3 receptor binding sites, probably by selective adjustment of hislamine neurons in response to unilateral enucleation, and the tip-regulated H3 receptors caused by denervation were coupled with G proteins.