Cholinergic mesencephalic neurons are involved in gait and postural disorders in Parkinson disease.

Gait disorders and postural instability, which are commonly observed in elderly patients with Parkinson disease (PD), respond poorly to dopaminergic agents used to treat other parkinsonian symptoms. The brain structures underlying gait disorders and falls in PD and aging remain to be characterized. Using functional MRI in healthy human subjects, we have shown here that activity of the mesencephalic locomotor region (MLR), which is composed of the pedunculopontine nucleus (PPN) and the adjacent cuneiform nucleus, was modulated by the speed of imagined gait, with faster imagined gait activating a discrete cluster within the MLR.

Pharmacological characterization of a selective agonist for bombesin receptor subtype-3.

Bombesin receptor subtype-3 (BRS-3) is an orphan G protein-coupled receptor in the bombesin receptor family that still awaits identification of its natural ligand. BRS-3 deficient mice develop a mild late-onset obesity with metabolic defects, implicating BRS-3 plays a role in feeding and metabolism. We describe here the pharmacological characterization of a synthetic compound, 16a, which serves as a potent agonist for BRS-3.

Fusion of diphtheria toxin and urotensin II produces a neurotoxin selective for cholinergic neurons in the rat mesopontine tegmentum.

Urotensin II is a neuropeptide first isolated from fish and later found in mammals: where it has potent cardiovascular, endocrine and behavioral effects. In rat brain the urotensin II receptor (UII-R) is predominately expressed in the cholinergic neurons of the pedunculopontine (PPTg) and laterodorsal tegmental nuclei. Typically, the function of the PPTg has been examined using excitotoxins, destroying both cholinergic and non-cholinergic neurons, which confounds interpretation.

A Drosophila adenosine receptor activates cAMP and calcium signaling.

Adenosine receptors (AdoR) are members of the G protein-coupled receptor superfamily and mediate extracellular adenosine signaling, but the mechanism of adenosine signaling is still unclear. Here we report the first characterization of an insect AdoR, encoded by the Drosophila gene CG9753. Adenosine stimulation of Chinese hamster ovary cells carrying transiently expressed CG9753 led to a dose-dependent increase of intracellular cAMP and calcium, but untransfected controls showed no such response, showing that CG9753 encodes a functional AdoR.

Differential expression of the thyrostimulin subunits, glycoprotein alpha2 and beta5 in the rat pituitary.

Two glycoprotein hormone subunits, (glycoprotein hormone alpha2-subunit GPA2) and (glycoprotein hormone beta5-subunit GPB5) have been recently discovered which, when expressed in vitro, heterodimerize to form a new hormone called thyrostimulin. Thyrostimulin activates the thyroid-stimulating hormone receptor (TSHR) and has thyrotropic activity. Immunological studies have indicated that both subunits co-localize in pituitary cells.