“…It has been postulated that the pacemaker properties arise from intrinsic voltage-dependent conductances that confer increases in burst frequency at depolarized membrane potentials and decreases, to the point of inhibiting rhythmic bursting, at hyperpolarized membrane potentials Butera et al, 1999a,b). The primary conditioning excitatory drive that maintains the oscillatory state arises from activation of glutaminergic receptors (Greer et al, 1991;Funk et al, 1993). Additional conditioning is provided by a diverse group of neuromodulators, including GABA, serotonin, noradrenaline, opioids, prostaglandins, substance P, and acetylcholine (Lagercrantz, 1987;Moss and Inman, 1989;Ballanyi et al, 1999).…”