Nitrergic innervation of the cerebral arterial tree in the bent-winged bat (mammalia: Microchiroptera)

Colocalization of nitric oxide synthase, vasoactive intestinal polypeptide and tyrosine hydroxylase immunoreactivities in postganglionic neurons of the quail superior cervical ganglion

The colocalization of immunoreactivity to nitric oxide synthase (NOS), vasoactive intestinal polypeptide (VIP) and tyrosine hydroxylase (TH) in the superior cervical ganglion (SCG) was investigated in the quail. In this bird, a substantial amount of NOS-immunoreactive (IR) cells were consistently found in the SCG without colchicine treatment or nerve ligation. The finding worthy of pointing out was that three-fourths of these NOS-IR cells were positive for TH. VIP-IR cells appeared with markedly low frequency than NOS-IR cells. They were generally small in size and often located in the ganglion peripheral. There were no VIP-IR cells positive for TH or negative for NOS: VIP immunoreactivity always appears in NOS-IR cells negative for TH. Thus, the results of the present study clearly showed the existence of two distinct subpopulations of postganglionic NOS-IR neurons (one is catecholaminergic and negative for VIP, and the other is non-catecholaminergic and positive for VIP). This suggests that nitric oxide (NO) and possibly VIP act as postganglionic neurotransmitters or neuromodulators in the quail SCG. The predominant appearance of the former category of NOS-IR cells must be considered in relation to some specific NO-induced controlling mechanisms of SCG neurons.

Separate development of nitric oxide synthase- and vasoactive intestinal polypeptide-immunoreactive nerves arising from the vertebral artery in the rat

Development of nitric oxide synthase (NOS)-and vasoactive intestinal polypeptide (VIP)-immunoreactive (-IR) nerves supplying the basilar and vertebral arteries (BA and VA) was investigated in White Wistar rats, using double immunohistochemistry. NOS-IR and VIP-IR nerves via the anterior circulation (AC), which mostly expressed NO(+)/VIP(+), extended to the BA during the second postnatal week, and usually reached as far as the rostral two third of the BA on PND 20. NOS-IR nerves were completely lack in the cBA and the VA on PND10, and often absent from these arterial regions even at PND 20. Nevertheless, a small number of VIP(+)/NOS(-) nerves were localized in the walls from the caudal BA (cBA) to the VA on PND 5. On PND 20, they frequently met with the descending NOS-IR and VIP-IR nerves via the AC around the lower portion of the middle BA. Fiber bundles containing NOS(+)/VIP(+) axons were first visualized on the caudal VA at PND 30 and observed frequently at PND 80, with a distinct increase in number of NOS-IR and VIP-IR nerves supplying the cBA and the VA. Thus, NOS-IR nerves coming from the VA develop through its own characteristic sequence that lags markedly behind the time of appearance for VIP-IR nerves from the same vascular route and for NOS-IR and VIP-IR nerves via the AC.

Development of nitric oxide synthase-immunoreactive nerves in the cerebral arteries of the rat

Development of cerebrovascular nitrergic nerves was investigated in the rat, using immunohistochemistry for nitric oxide synthase (NOS) and quantitative analysis. Cerebral perivascular NOS nerves usually appeared on the walls of both the intracranial part of the internal carotid artery (ICA) and the internal ethmoidal arteries (IEA) at birth. NOS nerves via the IEA grew more rapidly than those via the ICA. They extended over all the major arteries located more rostral than the middle part of the basilar arteries during the third postnatal week, while those from the ICA remained limited to the caudal segment of the anterior circulation and to the rostral segment of the posterior circulation throughout development. The appearance of NOS nerves on the vertebrate artery (VA) was not demonstrated before the third postnatal week, being apparently far late in development as compared to that of the same nerve type on the ICA and IEA.