Origin and co‐localization of nitric oxide synthase, CGRP, PACAP, and VIP in the cerebral circulation of the rat

Abstract

The origin of perivascular nerve fibres storing nitric oxide synthase (NOS) and co-localisation with perivascular neuropeptides were examined in the rat middle cerebral artery (MCA) by retrograde tracing with True Blue (TB) in combination with immunocytochemistry. Application of TB to the proximal part of the middle cerebral artery labelled nerve cell bodies ipsilaterally in the trigeminal, sphenopalatine, otic, and superior cervical ganglia. A few labelled cell bodies were seen contralaterally, suggesting bilateral innervation. In the parasympathetic sphenopalatine and otic ganglia, numerous TB-labelled cell bodies contained neuronal NOS (C- and N-terminal), vasoactive intestinal peptide (VIP), and pituitary adenylate cyclase activating peptide (PACAP). In the trigeminal ganglion, almost all TB-labelled cell bodies contained calcitonin gene-related peptide (CGRP) but only a few cells contained NOS. In the superior cervical ganglion, the majority of the TB-labelled nerve cells contained neuropeptide Y (NPY) but none of them contained NOS. Removal of the ipsilateral sphenopalatine ganglion caused a slight reduction in the number of perivascular VIP-, PACAP-, and NOS-containing fibres after 3 days in the MCA while there was no difference at 2 and 4 weeks after the denervation as compared to control. This indicates that the parasympathetic VIP-, PACAP-, and NOS-immunoreactive nerve fibres in the rat MCA originate from several sources.

Development of Nitric Oxide Synthase-Immunoreactive Nerves in the Cerebral Arteries of the Rat

“…Since similar pattern of VIP and AChE neuronal projection to the two cerebral arterial systems from the otic ganglion and the internal carotid mini ganglia via the ICA has been delineated in the adult rat [17,18], these two parasympa- thetic ganglia may also contribute to the cerebrovascular NOS innervation through this neuronal pathway. Indeed, the observation that some of the neurons in the otic ganglion, which are labeled with the application of a retrograde axonal tracer, True Blue, to the MCA, are also immunoreactive for NOS has recently been reported for the rat [8]. Accordingly, a few NOS nerve cells, which were localized in the ICA and its neighborhood of each one individual at PND 3 and 5, may be interpreted as being an accidental outflow tract from these cranial facial ganglia.…”

“…Thus, neurons synthesizing NO, nitrergic neurons, can be visualized by immunohistochemical staining with an antibody against neuronal NOS, or by histochemistry for nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd). Actually, by mean of these two staining methods, the rich supply of nerves immunoreactive for NOS and positive NADPHd has been demonstrated for the cerebral arterial systems in a variety of mammals including man [1,4,8,10,12,15,22]. Some of these studies, in combination with denervation and/or retrograde tracing techniques, have also provided conclusive evidence that cerebral perivascular NOS and NADPHd nerves, as well as nerves positive for acetylcholinesterase (AChE) and immunoreactive for vasoactive intestinal polypeptide (VIP), are parasympathetic in nature and have their major origin at the sphenopalatine ganglion.…”

The PACAP Receptor: A Novel Target for Migraine Treatment

“…18 The N-terminal 28 amino acids of PACAP-38 share 68% homology with VIP, 19 and the two related peptides are colocalized in rat parasympathetic ganglia. 5,20 The action of PACAP is mediated through three Gprotein coupled receptors: VPAC 1 and VPAC 2 , which have an equally high affinity for PACAP and VIP, and PAC 1 , which has a 1000-fold higher affinity for PACAP than for VIP. 21 Activation of all three receptors increases cAMP; phospholipase C (PLC) and intracellular calcium have also been reported as effector pathways 22,23 (FIG.…”

Electrophysiological and immunofluorescence characterization of Ca2+ channels of acutely isolated rat sphenopalatine ganglion neurons

“…Both VIP and Ang II aid in regulating cerebral blood flow and SPG neurons have been shown to stain positive for VIP [6,17]. VIP activates vasoactive intestinal peptide/pituitary adenylate cyclase activating polypeptide receptor-1 (VPAC1) and receptor-2 (VPAC2) that are coupled to G# s protein subunits [11], while Ang II stimulates angiotensin II types I and 2 (AT1 & AT2) G# q/11 -coupled receptors [17].…”