Adrenergic signalling between rat taste receptor cells.
In taste buds, synaptic transmission is traditionally thought to occur from taste receptor cells to the afferent nerve. This communication reports the novel observation that taste receptor cells respond to adrenergic stimulation. Noradrenaline application inhibited outward potassium currents in a dose-dependent manner. This inhibition was mimicked by the beta agonist isoproterenol and blocked by the beta antagonist propranolol. The alpha agonists clonidine and phenylephrine both inhibited the potassium currents and elevated intracellular calcium levels. Inwardly rectifying potassium currents were unaffected by adrenergic stimulation. Experiments using the RT-PCR technique demonstrate that lingual epithelium expresses multiple alpha (alpha1a, alpha1b, alpha1c, alpha1d, alpha2a, alpha2b, alpha2c) and beta (beta1, beta2) subtypes of adrenergic receptors, and immunocytochemistry localized noradrenaline to a subset of taste receptor cells. Collectively, these data imply strongly that adrenergic transmission within the taste bud may play a paracrine role in taste physiology.
Herness
Scott
S
Department of Oral Biology, College of Dentistry, Ohio State University, 305 West 12th Avenue, Columbus, OH 43210, USA. herness.1@osu.edu
Zhao
Fang-Li
FL
Kaya
Namik
N
Lu
Shao-Gang
SG
Shen
Tiansheng
T
Sun
Xiao-Dong
XD
D000316:Adrenergic alpha-Agonists / Q000032:analysis / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D004847:Epithelial Cells / Q000502:physiology; D015870:Gene Expression; D007150:Immunohistochemistry; D007545:Isoproterenol / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009475:Neurons, Afferent / Q000737:chemistry / Q000502:physiology*; D009638:Norepinephrine / Q000032:analysis / Q000494:pharmacology; D019899:Paracrine Communication / Q000187:drug effects / Q000502:physiology; D011188:Potassium / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011942:Receptors, Adrenergic, alpha / Q000235:genetics / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000235:genetics / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D013649:Taste / Q000502:physiology*; D013650:Taste Buds / Q000737:chemistry / Q000502:physiology*
D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D024661:Potassium Channels, Inwardly Rectifying; D012333:RNA, Messenger; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D007545:Isoproterenol; D011188:Potassium; D009638:Norepinephrine