Cimino M, Marini P, Colombo S, Andena M, Cattabeni F, Fornasari D, Clementi F
Institute of Pharmacology and Pharmacognosy, University of Urbino, Milan, Italy.
J Neural Transm Gen Sect. 1995;100(2):77-92. doi: 10.1007/BF01271531.
The expression of the alpha 4 and beta 2 subunits of neuronal nicotinic acetylcholine receptors (nAChRs) was studied in developing rat brain using in situ hybridization. The levels of both transcripts were already high at birth in cerebral cortex, medial habenula, CA1/CA3 regions of the hippocampus and several thalamic nuclei. In general, the beta 2 subunit showed a higher density of hybrids than the alpha 4. Beta 2 expression did not change with age in the medial habenula, medial geniculate nucleus or in the hippocampus whereas it decreased in the cortex. The developmental pattern of the hybridization signal for alpha 4 was different according to the brain area considered. The expression of the two transcripts showed a biphasic pattern in some thalamic nuclei: the lowest levels occurring during the first and second postnatal weeks respectively, and the highest levels during the second and fourth postnatal weeks. The ontogenetic profile of the expression of the alpha 4 subunit in the thalamic nuclei coincided with that of [3H]-L-nicotine binding sites. These findings suggest that the two subunits of nAChRs are independently regulated in most of the brain areas examined, and that in some regions, such as the thalamus, the ontogenetic variations reported for the alpha 4 subunit correlate with those observed for the [3H]-L-nicotine binding sites.
利用原位杂交技术，研究了发育中大鼠脑内神经元烟碱型乙酰胆碱受体（nAChRs）α4和β2亚基的表达情况。出生时，大脑皮质、内侧缰核、海马CA1/CA3区以及几个丘脑核团中这两种转录本的水平就已经很高。总体而言，β2亚基显示出比α4更高的杂交信号密度。在内侧缰核、内侧膝状体核或海马中，β2的表达不随年龄变化，而在皮质中其表达则下降。α4杂交信号的发育模式因所考虑的脑区而异。在一些丘脑核团中，这两种转录本的表达呈现双相模式：分别在出生后的第一周和第二周出现最低水平，在出生后的第二周和第四周出现最高水平。丘脑核团中α4亚基表达的个体发育概况与[3H]-L-尼古丁结合位点的情况一致。这些发现表明，在所检查的大多数脑区中，nAChRs的两个亚基是独立调节的，并且在某些区域，如丘脑，所报道的α4亚基的个体发育变化与[3H]-L-尼古丁结合位点所观察到的变化相关。
