Dendritic synthesis and release of the neuropeptide galanin: morphological evidence from studies on rat locus coeruleus neurons.

Dendritic synthesis and release of neuropeptides have been demonstrated in hypothalamic neurosecretory neurons. Here we tested whether this mechanism may be applicable to galanin in rat locus coeruleus (LC) neurons. Light and electron microscopic immunocytochemistry demonstrated the occurrence of galanin peptide in secretory granules within dendritic processes.

Immunogold detection of co-localized neuropeptides: methodological aspects.

Whatever the protocol used, electron microscopic immunogold detection still suffers from a lack of sensitivity. In rat supraoptico-posthypophyseal neurons, unlabeled secretory granules are always detectable after electron microscopic immunocytochemistry, and their real status remains questionable. To improve the sensitivity of this approach, we assessed a protocol to visualize either one or the other of co-localized neuropeptides, i.

Differential routing of coexisting neuropeptides in vasopressin neurons.

The functional implications of intraneuronal coexistence of different neuropeptides depend on their respective targeting to release sites. In the rat hypothalamic magnocellular neurons, we investigated a possible differential routing of the coexpressed galanin and vasopressin. The respective location of proteins and messengers was assessed with double immunogold and in situ hybridization combining confocal and electron microscope analysis.

Differential routing of coexisting neuropeptides in vasopressin neurons.

The functional implications of intraneuronal coexistence of different neuropeptides depend on their respective targeting to release sites. In the rat hypothalamic magnocellular neurons, we investigated a possible differential routing of the coexpressed galanin and vasopressin. The respective location of proteins and messengers was assessed with double immunogold and in situ hybridization combining confocal and electron microscope analysis.