Fine structure of the pinealopetal innervation of the mammalian pineal gland

Abstract

The mammalian pineal gland is innervated by peripheral sympathetic and parasympathetic nerve fibers as well as by nerve fibers originating in the central nervous system (central innervation). The perikarya of the sympathetic fibers are located in the superior cervical ganglia, while the fibers terminate in boutons containing small granular vesicles and a few large granular vesicles. Both noradrenaline and neuropeptide Y are contained in these neurons. The parasympathetic fibers originate from perikarya in the pterygopalatine ganglia. The neuropeptides, vasoactive intestinal peptide and peptide histidine isoleucine, are present in these fibers, the boutons of which contain small clear transmitter vesicles and larger granular vesicles. The fibers of the central innervation originate predominantly from perikarya located in hypothalamic and limbic forebrain structures as well as from perikarya in the optic system. These fibers terminate in boutons containing small clear and, in certain fibers, an abundant number of large granular vesicles. In rodents, the majority of the central fibers terminate in the deep pineal gland and the pineal stalk. From these areas impulses might be transmitted further caudally to the superficial pineal gland via neuronal structures or processes from pinealocytes. Several hypothalamic neuropeptides and monoamines might be contained in the central fibers. The intrapineal nerve fibers are located both in the perivascular spaces and intraparenchymally. The majority of the intraparenchymally located fibers terminate freely between the pinealocytes. However, some nerve terminals make synaptic contacts with the pinealocytes and in some species with intrapineal neurons. In fetal mammals, sympathetic, parasympathetic, and central fibers are also present. In addition, an unpaired nerve, connecting the caudal part of the pineal gland with the extreme rostral part of the mesencephalon, is present. This nerve is a homologue to the pineal nerve (nervus pinealis) observed in lower vertebrates.

Innervation of the rat pineal gland by nerve fibres originating in the sphenopalatine, otic and trigeminal ganglia. A retrograde in vivo neuronal tracing study

“…Les [15]) and by nerve fibres originating from the perikarya located in the peripheral ganglia (for review, see [17]). …”

Estudo dos efeitos da melatonina sobre danos ao DNA induzidos pela ciclofosfamida em ratos wistar pinealectomizados.

“…Estas células diferenciam-se nas células parenquimatosas do corpo pineal ou pinealócitos. Deste modo, durante a evolução, o corpo pineal passou de um órgão sensorial para um órgão parenquimatoso e secretor (MØLLER, 1992).…”

“…Além desses elementos, a pineal é muito vascularizada e seu fluxo sangüíneo foi estimado em 4ml/min/g e é superado apenas pelo rim. A inervação da pineal se faz por fibras simpáticas pós-ganglionares, oriundas do gânglio cervical superior (MØLLER, 1992;MACCHI e BRUCE, 2004).…”

Os efeitos do treinamento físico aeróbio sobre a síntese de melatonina pineal em ratos.

“…A pineal profunda, ou lâmina intercalar, está localizada entre as comissuras posterior e habenular, delimitando uma região ventricular chamada de recesso pineal, e da sua porção dorsal emerge o pedúnculo pineal que se comunica com a pineal superficial (MOLLER, 1992).…”