Neural effects of parathyroid hormone: modulation of the calcium channel current and metabolism of monoamines in identified Helisoma snail neurons.
Neuronal effects of parathyroid hormone (PTH) have been reported in vertebrates. The effect of PTH on invertebrate central neurons within the buccal ganglion of Helisoma trivolvis snails was examined in the present study. By using a vibrating probe, PTH was found to induce a transient calcium-dependent inward current in intact buccal ganglia. Intracellular microelectrode recording revealed that PTH broadened the spontaneous action potential in buccal B5 neurons in situ. By using the whole-cell configuration of the patch-clamp technique, PTH was demonstrated to increase the N-like calcium channel currents in isolated B5 neurons in a concentration-dependent manner. This effect of PTH on the N-like calcium channel currents depended on the activation of a G protein insensitive to pertussis toxin, but was unlikely to be mediated by the cyclic AMP dependent protein kinase. Furthermore, the release of gamma-glutamyl conjugate of dopamine from buccal ganglia was selectively increased in the presence of PTH. These results represent the first demonstration that a vertebrate peptide hormone, PTH, selectively modulates the N-like voltage-dependent calcium channel currents in identified invertebrate neurons. Therefore, a novel role of PTH in the regulation of invertebrate central neural functions is indicated.
Wang
R
R
Department of Physiology, University of Montréal, QC, Canada.
Pang
P K
PK
Wu
L
L
Shipley
A
A
Karpinski
E
E
Harvey
S
S
Berdan
R C
RC
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology*; D004298:Dopamine / Q000031:analogs & derivatives / Q000378:metabolism; D017952:Ganglia, Invertebrate / Q000502:physiology; D006706:Homeostasis / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology; D009474:Neurons / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000502:physiology*; D012908:Snails / Q000502:physiology*
D015306:Biogenic Monoamines; D015220:Calcium Channels; D010281:Parathyroid Hormone; C034720:gamma-glutamyl dopamine; D004298:Dopamine