trkA, CGRP and IB4 expression in retrogradely labelled cutaneous and visceral primary sensory neurones in the rat.

The pattern of trkA expression in relation to other neurochemical markers (CGRP and IB4) was investigated in primary sensory neurones innervating either the skin or bladder. Retrograde tracing using the fluorescent marker Fast Blue was performed followed by histochemistry. A greater proportion of visceral afferents compared with cutaneous afferents were trkA-immunoreactive (75% and 43%, respectively).

Expression of GAP-43 mRNA in preganglionic sympathetic neurones of the adult rat spinal cord.

In situ hybridization combined with intraperitoneal injection of the tracer Fluoro-Gold was used to study the distribution of GAP-43 mRNA in autonomic cell groups of the rat spinal cord. In the thoracic cord, numerous cells expressing GAP-43 mRNA were present in the central autonomic nucleus (lamina X) and in the intermediolateral cell column (IML). In the IML, all Fluoro-Gold-labelled preganglionic neurones were heavily labelled for GAP-43 mRNA.

Immunocytochemical localization of trkA receptors in chemically identified subgroups of adult rat sensory neurons.

Immunocytochemistry has been used to examine the location of trkA, the high-affinity receptor for nerve growth factor, in adult rat dorsal root ganglia, trigeminal ganglia and spinal cord. TrkA immunoreactivity was observed in small and medium sized ganglion cells and in the dorsal horn of the spinal cord. In lumbar L4 and L5 ganglia trkA-immunoreactive cells constitute 40% of dorsal root ganglion cells and range in size from 15 to 45 microns in diameter.

Serotonergic terminals express a growth associated protein (GAP-43) in the adult rat spinal cord.

Dual colour immunofluorescence has been used to compare the distribution of serotonin (5-hydroxytryptamine, 5-HT) and GAP-43 in the adult rat. GAP-43 immunostaining was observed in all spinal cord regions containing 5-HT immunoreactivity. 5-HT and GAP-43 double labelled fibres and varicosities were present and were most evident around motoneurones, in lamina X, and in the intermediolateral cell column.

Enkephalin and serotonin innervation of somatostatin-immunoreactive medullary reticular formation neurones.

Somatostatin cells in the rat medullary reticular formation (Md) have been studied using peroxidase-antiperoxidase immunocytochemistry. Large fusiform and multipolar somatostatin immunoreactive cells were observed in the ventral subnucleus (MdV) running in a band close to the border with the dorsal subnucleus (MdD). In the same region somatostatin-, serotonin- and enkephalin-immunoreactive fibres occur and double staining revealed that these all contact the somatostatin-immunoreactive cells, with enkephalin making a particularly dense innervation.

Anatomy of somatostatin-immunoreactive fibres and cell bodies in the rat trigeminal subnucleus caudalis.

The distribution of somatostatin-immunoreactive fibres and cells has been analysed in the rat spinal trigeminal subnucleus caudalis. Immunoreactive fibres are most concentrated in lamina II outer but fibres and terminals occur also in lamina I, lamina II inner, and scattered in the magnocellular region and neighbouring lateral reticular area. Immunoreactive cells occur in laminae I and II and in the magnocellular region of the nucleus but are most abundant in lamina II inner.

Ultrastructure of somatostatin-immunoreactive nerve terminals in laminae I and II of the rat trigeminal subnucleus caudalis.

The morphology and distribution of somatostatin-immunoreactive synaptic boutons was studied in the rat trigeminal subnucleus caudalis using pre-embedding electron microscopic techniques. Immunoreactive terminals were found in lamina I and throughout lamina II but were more concentrated in outer lamina II. All immunoreactive terminals contained many round or pleomorphic agranular small synaptic vesicles and some large dense-cored vesicles.

Extra-cutaneous melanin.

Extra-cutaneous melanocytes derive from either the neural crest, the outer wall of the optic cup, or the cranial neural tube. Those of neural crest origin reach most bodily regions, and may give rise to primary melanoma in various tissues. The Kupffer cell produces a form of melanin, but is hardly a melanocyte.