Bulc M, Lewczuk B
Department of Clinical Physiology, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Oczapowskiego 13, 10-719 Olsztyn, Poland.
Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Oczapowskiego 13, 10-719 Olsztyn, Poland.
Folia Morphol (Warsz). 2019;78(4):695-702. doi: 10.5603/FM.a2019.0024. Epub 2019 Mar 5.
The study demonstrates, for the first time, the presence of substance P (SP) and calcitonin gene-related peptide (CGRP) in the nerve fibres supplying the pineal gland in the Arctic fox.
The expression and distribution pattern of the studied substances were examined by double-labelling immunofluorescence technique.
The SP-positive fibres enter into the pineal gland through the capsule as the nervi conarii. The fibres formed thick bundles in the capsule and connective tissue septa, from where they penetrated into the pineal parenchyma. Inside the parenchyma, the nerve fibres created basket-like structures surrounding clusters of pinealocytes. The density of intrapineal SP positive fibres was slightly higher in the distal and middle parts of the gland than in the proximal one. Double immunostaining with antibodies against SP and CGRP revealed that the vast majority of SP positive fibres were also CGRP positive. The fibres showing a positive reaction to SP and negative to CGRP were scattered within the whole gland. The fibres immunopositive to CGRP and immunonegative to SP were not observed. In the habenular and posterior commissural areas adjoining to the pineal gland the immunoreactive nerve fibres were not found. Moreover, no immunopositive cell bodies were observed in both the pineal gland and the commissural areas.
These results reveal that SP and CGRP are involved in the innervation of pineal gland in carnivores. In turn we suggest that these peptides can regulate/modulate melatonin secretion.
本研究首次证实北极狐松果体的神经纤维中存在P物质（SP）和降钙素基因相关肽（CGRP）。
采用双重免疫荧光技术检测所研究物质的表达及分布模式。
SP阳性纤维作为松果体神经经被膜进入松果体。这些纤维在被膜和结缔组织间隔中形成粗大的束状结构，由此穿入松果实质。在实质内，神经纤维围绕松果体细胞簇形成篮状结构。松果体内SP阳性纤维的密度在腺体的远端和中部略高于近端。用抗SP和CGRP抗体进行双重免疫染色显示，绝大多数SP阳性纤维也为CGRP阳性。对SP呈阳性反应而对CGRP呈阴性反应的纤维散在于整个腺体中。未观察到对CGRP免疫阳性而对SP免疫阴性的纤维。在与松果体相邻的缰核和后连合区域未发现免疫反应性神经纤维。此外，在松果体和连合区域均未观察到免疫阳性细胞体。
这些结果表明SP和CGRP参与了食肉动物松果体的神经支配。进而我们认为这些肽可调节褪黑素的分泌。
