Pacemaker Currents in Dopaminergic Neurones of the Mice Olfactory Bulb

In the olfactory bulb (OB) dopaminergic (DA) neurones constitute a fraction of the cells occupying the most external (glomerular) layer (Halasz et al.1977). In this region, populated by three types of interneurons, periglomerular (PG) cells, short-axon cells and external tufted (ET) cells (Halasz1990) often collectively referred to as juxtaglomerular cells an estimated 10% of the neurones in adulthood are positive for tyrosine hydroxylase (TH) (McLean and Shipley1988; Kratskin and Belluzzi2003), the rate limiting enzyme for dopamine synthesis. Dopaminergic neurones in the glomerular layer include PG cells (Gall et al.1987; Kosaka et al.1985) and a fraction of ET cells (Halasz1990). Several studies have focused on the role of dopamine in the olfactory bulb, using immunohistochemical (Baker et al.1983; Guthrie et al.1991), behavioral (Doty and Risser1989), and electrophysiological techniques (Nowycky et al.1983; Ennis et al.2001; Davila et al.2003). The more complete description of the functional properties of DA neurons in the OB is probably the paper of Pignatelli (Pignatelli et al.2005), but it was incomplete, as it did not consider the contribution of the inward rectifier currents, a lacuna which is filled in the present work.