+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Pharmacological evidence for two types of postsynaptic glycinergic receptors on the Mauthner cell of 52-h-old zebrafish larvae

, : Pharmacological evidence for two types of postsynaptic glycinergic receptors on the Mauthner cell of 52-h-old zebrafish larvae. Journal of Neurophysiology 77(5): 2400-2415

The presence of homooligomeric and heterooligomeric glycine receptors (GlyRs) on the Mauthner (M) cell in the isolated medulla of 52-h-old zebrafish larvae was investigated by analysis of the effects of picrotoxin on glycine-gated channels and on glycinergic miniature inhibitory postsynaptic currents (mIPSCs). Two functionally different GlyRs have been previously described on the M cell. The effects of picrotoxin on these two GlyRs were first analyzed by measuring the relative change in their total open probability (NP(o)) with picrotoxin concentration. Picrotoxin had no significant effect on the glycine channel with a single conductance level of 40-46 pS. In contrast, picrotoxin application decreased the NP(o) of the GlyR with multiple subconductance levels. On this GlyR, picrotoxin decreased in a concentration-dependent manner the occurrence of the 80- to 86-pS substate (median inhibiting concentration = 0.89 microM) and had no apparent effect on the 40- to 46-pS opening probability. Opening frequency and the mean open times of the 80- to 88-pS main conductance state were reduced in the presence of 10 microM picrotoxin, but their relative weight remained unchanged. These effects of picrotoxin were not voltage dependent. Picrotoxin also modified 40- to 46-pS kinetics. At 100 microM, picrotoxin evoked voltage-independent flickering during channel openings. Short and long mean open times were significantly decreased, whereas the relative proportion of long mean open times was increased. The medium closed time was decreased, whereas medium burst duration was increased. The burst frequency remained unchanged. Spontaneous glycinergic mIPSCs were recorded in the presence of 1 microM tetrodotoxin + 25 microM bicuculline (holding potential = -50 mV). Application of 10 microM picrotoxin did not change the frequency of the synaptic activity, whereas it decreased the amplitude of large mIPSCs. No effect was observed on the time to peak (0.8 ms) or the mean decay time constant (tau(d) = 7.7 ms). Increasing picrotoxin concentration to 100 microM resulted in a decrease of mIPSC frequency (35.6%), amplitude (39.8%), and tau(d) (from 7.7 to 5 ms). These results suggest that these two functionally different GlyRs correspond to alpha1 homooligomeric-like and alpha1/beta-heterooligomeric-like GlyRs, and that both are synaptically activated. Variation in the proportions of GlyR subtypes from one synapse to another could partly account for the broad amplitude distribution of mIPSCs recorded from the zebrafish M cell.


PMID: 9163366

Other references

Fernandes, L.; Linder, J.; Krock, L.P.; Balldin, U.I.; Harms-Ringdahl, K., 2003: Muscle activity in pilots with and without pressure breathing during acceleration. Background: Fighter pilots are frequently exposed to high acceleration (+Gz) forces during sorties. To counter these forces the pilots wear anti-G ensembles, use positive pressure breathing for G protection (PBG), and perform anti-G straining mane...

Weekes, A.J.; Oh, L.; Thacker, G.; Johnson, A.K.; Runyon, M.; Rose, G.; Johnson, T.; Templin, M.; Norton, H.James., 2016: Interobserver and Intraobserver Agreement on Qualitative Assessments of Right Ventricular Dysfunction With Echocardiography in Patients With Pulmonary Embolism. To evaluate observer agreement using qualitative goal-directed echocardiographic criteria for right ventricular (RV) dysfunction prognostication in submassive pulmonary embolism (PE). Two emergency physicians and 2 cardiologists independently revi...

Chapman, A.G., 1999: Glutamate receptors in epilepsy. Glutamatergic synapses play a critical role in all epileptic phenomena. Broadly enhanced activation of post-synaptic glutamate receptors (ionotropic and metabotropic) is proconvulsant. Antagonists of NMDA receptors and AMPA receptors are powerful...

Greene, N.M., 1960: Anesthesia in obstetrics and gynecology. Transactions of the New England Obstetrical and Gynecological Society 14: 27-35

Wodak, H., 1939: A preliminary note on the influence of hen egg yolk on hemopoiesis. Feeding egg yolk to patients suffering from anaemia resulted in an increase in erythro cytes and Hb but not in reticulocytes. The haematopoietic action of fish roe was smaller than that of egg yolk but Was increased by injections of lactoflavin. P...

Schramm, G.; Mohr, E., 1959: Purification of neuraminidase from Vibrio cholerae. Nature 183(4676): 1677-1678

Walter, E.; Staiger, C.; de Vries, J.; Weber, E.; Bitzer, W.; Degott, M.; Jüngling, K., 1982: Enhanced drug metabolism after sulfinpyrazone treatment in patients aged 50 to 60 years. The induction of liver drug metabolism was investigated in five patients before and after the administration of 800 mg sulfinpyrazone daily for 4 weeks, by using antipyrine plasma-pharmacokinetics and by determining urinary excretion of 6-beta-OH-...

van Dantzig, N.A.; Planken, P.C.; Bakker, H.J., 2007: Far-infrared second-harmonic generation and pulse characterization with the organic salt DAST. We generated the second harmonics of pulses in the far-infrared region (30-55 microm), using the organic salt dimethylamino-4-N-methylstilbazolium tosylate (DAST). We demonstrate that DAST can be used to characterize ultrashort pulses in a spectra...

Kolesnik, E.A.; Goncharuk, B.A.; Kamenev, B.A.; Rudnitskiĭ, S.V., 1977: Treatment of lumbosacral radiculitis using thermocontrast mud baths. Vrachebnoe Delo: 117-119

Subramaniam, M.;, B.; Taylor, N.Greene.; Kodama, C.; Follman, R.; Casciotti, D., 2015: Bit by bit: using design-based research to improve the health literacy of adolescents. Although a low health literacy level has been found to be among the most powerful predictors of poor health outcomes, there is very little research focused on assessing and improving the health literacy skills of adolescents, particularly those fr...