Biomaterial Database

Electrophysiological evidence for the existence of separate receptor mechanisms mediating the action of 5-hydroxytryptamine. 1981

M J Berridge

The transepithelial potential recorded across the salivary gland of the blowfly Calliphora responded to 5-hydroxytryptamine (5-HT) with a complex depolarising response characterised by oscillatory activity at low doses. A rapid screening procedure for characterizing the electrophysiological response of the gland to 5-HT and its analogues was developed. It consisted of recording the potential during the gradual addition of the agent in the form of a ramp. 5-HT gave a characteristic electrophysiological signature which was then compared with that of other analogues. Tryptamine, bufotenine and dimethyltryptamine gave potential signatures very similar to those of 5-HT. Histamine, 4- and 5-fluoro-alpha-methyltryptamine gave s predominantly hyperpolarising response which is characteristic of the effect produced by cyclic AMP. Analogues with substituents at the 5-position (methyl, methoxy, chloro) and 4-hydroxytryptamine gave a depolarising response indicative of a predominantly calcium effect. It is concluded that 5-HT acts through separate transducing mechanisms. The depolarizing response seems to indicate an action through calcium whereas the hyperpolarizing response might be mediated through cyclic AMP. Whether or not these separate responses are linked to different 5-HT receptors remains to be determined.

UI	MeSH Term	Description	Entries
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D011985	Receptors, Serotonin	Cell-surface proteins that bind SEROTONIN and trigger intracellular changes which influence the behavior of cells. Several types of serotonin receptors have been recognized which differ in their pharmacology, molecular biology, and mode of action.	5-HT Receptor,5-HT Receptors,5-Hydroxytryptamine Receptor,5-Hydroxytryptamine Receptors,Receptors, Tryptamine,Serotonin Receptor,Serotonin Receptors,Tryptamine Receptor,Tryptamine Receptors,Receptors, 5-HT,Receptors, 5-Hydroxytryptamine,5 HT Receptor,5 HT Receptors,5 Hydroxytryptamine Receptor,5 Hydroxytryptamine Receptors,Receptor, 5-HT,Receptor, 5-Hydroxytryptamine,Receptor, Serotonin,Receptor, Tryptamine,Receptors, 5 HT,Receptors, 5 Hydroxytryptamine
D002027	Bufotenin	A hallucinogenic serotonin analog found in frog or toad skins, mushrooms, higher plants, and mammals, especially in the brains, plasma, and urine of schizophrenics. Bufotenin has been used as a tool in CNS studies and misused as a psychedelic.	Dimethylserotonin,Mappine,5-Hydroxy-N,N-dimethyltryptamine,Bufotenine,Mappin,N,N-Dimethyl-5-hydroxytryptamine,5 Hydroxy N,N dimethyltryptamine,N,N Dimethyl 5 hydroxytryptamine
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D004130	N,N-Dimethyltryptamine	An N-methylated indoleamine derivative and serotonergic hallucinogen which occurs naturally and ubiquitously in several plant species including Psychotria veridis. It also occurs in trace amounts in mammalian brain, blood, and urine, and is known to act as an agonist or antagonist of certain SEROTONIN RECEPTORS.	Dimethyltryptamine,N,N Dimethyltryptamine
D004175	Diptera	An order of the class Insecta. Wings, when present, number two and distinguish Diptera from other so-called flies, while the halteres, or reduced hindwings, separate Diptera from other insects with one pair of wings. The order includes the families Calliphoridae, Oestridae, Phoridae, SARCOPHAGIDAE, Scatophagidae, Sciaridae, SIMULIIDAE, Tabanidae, Therevidae, Trypetidae, CERATOPOGONIDAE; CHIRONOMIDAE; CULICIDAE; DROSOPHILIDAE; GLOSSINIDAE; MUSCIDAE; TEPHRITIDAE; and PSYCHODIDAE. The larval form of Diptera species are called maggots (see LARVA).	Flies, True,Flies,Dipteras,Fly,Fly, True,True Flies,True Fly
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D006632	Histamine	An amine derived by enzymatic decarboxylation of HISTIDINE. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.	Ceplene,Histamine Dihydrochloride,Histamine Hydrochloride,Peremin
D000242	Cyclic AMP	An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.	Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia