Ultrastructural localization of acetylcholinesterase in the guinea pig pineal gland

Luo, Zhongrong; Schultz, Robert L.; Whitter, Ernest F.

doi:10.1002/ar.1092260410

Cited by 7 publications

(1 citation statement)

References 40 publications

(33 reference statements)

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“…Ultrastructurally, AChE is present in many non-cholinergic neurons located in the cistern of the nuclear membrane, and in the axolemma of both unmyelinated and myelinated fibers (David and Kumar, 1978). The enzyme has also been demonstrated in a small number of guinea pig pinealocytes (Luo et al, 1990), and it is located in the perinuclear cisterns, the endoplasmic reticulum, and the Golgi apparatus.…”

Section: Presence Of Acetylcholinesterasementioning

confidence: 99%

Cholinergic innervation and function in the mammalian pineal gland

Phansuwan‐Pujito

Møller

Govitrapong

1999

Microsc. Res. Tech.

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Besides the noradrenergic sympathetic system originating from the superior cervical ganglion, a cholinergic innervation of the mammalian pineal gland has been studied over the past three decades. In 1961, it was shown that lesion of the parasympathetic greater superficial petrosal nerve of the monkey resulted in degeneration of nerve fibers in the pineal gland. This was supported by ultrastructural studies of nerve terminals within the pineal gland, demonstrating the presence of cholinergic terminals containing small clear transmitter vesicles. Biochemical studies further showed the presence of the enzyme acetylcholinesterase in several mammalian species. During the last decade, several advanced and more elaborate technologies have been developed, allowing pinealogists to establish the presence of cholinergic fibers and their receptors. Thus, choline acetyltransferase was shown in bovine pineal by immunohistochemistry. Muscarinic and nicotinic receptors were identified, characterized, and localized. Gene expression of receptors was visualized, and the receptor‐mediated effector systems and functions were elucidated. Taken together, the present data suggest the presence of a cholinergic innervation of the mammalian pineal gland originating in peripheral parasympathetic ganglia. However, some of the neuronal projections to the pineal gland with origin in the brain (the central innervation) might also be cholinergic. The cholinergic nerve fibers enter the gland, where they are located both in the perivascular spaces and between the pinealocytes. Some of the terminals make synapses on pinealocytes or intrapineal neurons. The released acetylcholine from the terminals interacts with the receptors, then alters the cascade of receptor‐mediated events, which results in decreased N‐acetyltransferase enzyme activity, thus leading to decreased melatonin synthesis. This counterbalance mechanism between the sympathetic noradrenergic and the cholinergic systems maintains the homeostasis of pineal functions. Microsc. Res. Tech. 46:281–295, 1999. © 1999 Wiley‐Liss, Inc.

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Section: Presence Of Acetylcholinesterasementioning

confidence: 99%

Cholinergic innervation and function in the mammalian pineal gland

Phansuwan‐Pujito

Møller

Govitrapong

1999

Microsc. Res. Tech.

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Cholinergic signaling in the rat pineal gland

Laitinen

Kokkola

1995

Cell Mol Neurobiol

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1. Innervation of the mammalian pineal gland is mainly sympathetic. Pineal synthesis of melatonin and its levels in the circulation are thought to be under strict adrenergic control of serotonin N-acetyltransferase (NAT). In addition, several putative pineal neurotransmitters modulate melatonin synthesis and secretion. 2. In this review, we summarize what is currently known on the pineal cholinergic system. Cholinergic signaling in the rat pineal gland is suggested based on the localization of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE), as well as muscarinic and nicotinic ACh binding sites in the gland. 3. A functional role of ACh may be regulation of pineal synaptic ribbon numbers and modulation of melatonin secretion, events possibly mediated by phosphoinositide (PI) hydrolysis and activation of protein kinase C via muscarinic ACh receptors (mAChRs). 4. We also present previously unpublished data obtained using primary cultures of rat pinealocytes in an attempt to get more direct information on the effects of cholinergic stimulus on pinealocyte melatonin secretion. These studies revealed that the cholinergic effects on melatonin release are restricted mainly to intact pineal glands since they were not readily detected in primary pinealocyte cultures.

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