Distribution of D2 dopamine receptor in the olfactory glomeruli of the rat olfactory bulb.

Dopamine plays key roles in the processing of the olfactory information that takes place in the olfactory glomeruli. Previous studies using autoradiography demonstrate that, at the glomerular level, these actions are mainly mediated via activation of D2 dopamine receptors. Moreover, it has been suggested that D2 receptors could be present in the olfactory nerve, where they might modulate the entrance of olfactory input into the brain.

Characterization of somatostatin- and cholecystokinin-immunoreactive periglomerular cells in the rat olfactory bulb.

Periglomerular cells (PG) are interneurons of the olfactory bulb (OB) that modulate the first synaptic relay of the olfactory information from the olfactory nerve to the dendrites of the bulbar principal cells. Previous investigations have pointed to the heterogeneity of these interneurons and have demonstrated the presence of two different types of PG. In the rat OB, type 1 PG receive synaptic contacts from the olfactory axons and are gamma-aminobutyric acid (GABA)-ergic, whereas type 2 PG do not receive synaptic contacts from the olfactory axons and are GABA immunonegative.

Soluble guanylyl cyclase appears in a specific subset of periglomerular cells in the olfactory bulb.

In the brain, nitric oxide acts as an atypical messenger in cellular nonsynaptic transmission. In the olfactory bulb, this gas is produced at the level of the olfactory glomeruli by a subpopulation of periglomerular cells that participates in the first synaptic relay of the olfactory information between the olfactory nerve and the dendritic tufts of principal cells. It has been proposed that nitric oxide modulates intraglomerular synaptic integration of sensory inputs, but its specific role in the glomerular circuitry remains to be understood.

Chelation of synaptic zinc induces overexcitation in the hilar mossy cells of the rat hippocampus.

Complete removal of synaptic zinc by the chelator dietyldithiocarbamate (DEDTC; 500 mg/kg i.p.) in rat was followed by convulsive behaviour including wet dog shakes alternating immobility.

VIP-containing deep short-axon cells of the olfactory bulb innervate interneurons different from granule cells.

This study investigates the targets of the population of vasoactive intestinal polypeptide (VIP)-containing deep short-axon cells of the rat olfactory bulb (OB), combining single- and double-immunocytochemical approaches under light and electron microscopy. It has been assumed that deep short-axon cells innervate granule cells in the mammalian OB, but their synaptic connectivity has not been demonstrated to date. Our results indicate that, instead of the accepted scheme of the bulbar circuitry, VIP-containing deep short-axon cells are gamma-aminobutyric acid (GABA)ergic interneurons specialized in the selective innervation of other GABAergic deep short-axon cells.

Nitric oxide synthase containing periglomerular cells are GABAergic in the rat olfactory bulb.

In the olfactory glomeruli of the rat olfactory bulb, there is a population of periglomerular cells (PG) that contains the neuronal isoform of the nitric oxide synthase (nNOS). To date, these PG have not been characterized neurochemically and it has not been determined whether they are type 1 (GABAergic PG that receive synaptic contacts from the olfactory axons) or type 2 PG (non-GABAergic PG that do not receive synapses from the olfactory axons). Combining pre-embedding NADPH-diaphorase histochemistry and post-embedding immunoperoxidase detection of GABA, we demonstrate that nNOS-containing PG are GABAergic and therefore, belong to the type 1 PG.