GABA and glycine have different effects on monaural response properties in the dorsal nucleus of the lateral lemniscus of the mustache bat. 1994

L Yang, and G D Pollak
Department of Zoology, University of Texas at Austin 78712.

1. We studied the monaural response properties of 81 neurons in the dorsal nucleus of the lateral lemniscus (DNLL) of the mustache bat before and during the iontophoretic application of antagonists that blocked gamma-aminobutyric acid-A (GABAA) receptors (bicuculline) or glycine receptors (strychnine). The main finding is that GABAergic inhibition had substantial effects, whereas glycine had little or no effect on the activity evoked by contralateral stimulation. 2. Before the application of drugs, the monaural response properties of DNLL cells were characterized by two main features. The first was that the majority (86%) of neurons had monotonic rate-intensity functions, whereas only 14% had weakly nonmonotonic functions. The second was that most (66%) neurons displayed some form of chopping response pattern, in which there was a regular interval between discharges that was unrelated to the period of the tone burst frequency. 3. Bicuculline had two major effects on the majority of DNLL cells. It caused large increases in spike counts and changes in temporal discharge patterns. In 38 of 47 cells (81%) bicuculline changed the temporal discharge patterns into a sustained chopper pattern. In addition, the duration of the discharge train continued for a period of time longer than the duration of the tone burst in many but not all neurons. Prolonged firing of this sort was rarely seen in the predrug condition. Furthermore, in a few cells bicuculline caused a decrease in the interspike interval as well as a lengthening of the discharge train. 4. Blocking glycine, in contrast, caused either small increases in spike count or no increase at all and did not affect the temporal discharge patterns in the majority (87%) of neurons. 5. In most DNLL cells the shapes of the rate-intensity functions were virtually the same before and during the application of either antagonist. The rate-intensity functions of 91% of the cells were unaffected by bicuculline and 98% were unaffected by strychnine. 6. Blocking either GABAergic inhibition or glycinergic inhibition had no effect on discharge latency in the vast majority of DNLL cells. In a few neurons application of bicuculline or strychnine had a small influence and caused discharge latency to decrease by < or = 1 ms. 7. These results show that the excitation from stimulation of the contralateral ear evokes a sustained chopping discharge pattern in the vast majority of DNLL neurons. The sustained chopping response is changed into another discharge pattern by the GABAergic innervation that is also evoked by stimulation of the contralateral ear.(ABSTRACT TRUNCATED AT 400 WORDS)

UI MeSH Term Description Entries
D007245 Inferior Colliculi The posterior pair of the quadrigeminal bodies which contain centers for auditory function. Colliculus, Inferior,Brachial Nucleus of the Inferior Colliculus,Caudal Colliculus,Colliculus Inferior,Inferior Colliculus,Posterior Colliculus,Colliculi, Inferior,Colliculus Inferiors,Colliculus, Caudal,Colliculus, Posterior,Inferior, Colliculus,Inferiors, Colliculus
D008144 Loudness Perception The perceived attribute of a sound which corresponds to the physical attribute of intensity. Loudness Perceptions,Perception, Loudness,Perceptions, Loudness
D009433 Neural Inhibition The function of opposing or restraining the excitation of neurons or their target excitable cells. Inhibition, Neural
D009474 Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM. Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D011149 Pons The front part of the hindbrain (RHOMBENCEPHALON) that lies between the MEDULLA and the midbrain (MESENCEPHALON) ventral to the cerebellum. It is composed of two parts, the dorsal and the ventral. The pons serves as a relay station for neural pathways between the CEREBELLUM to the CEREBRUM. Pons Varolii,Ponte,Pons Varolius,Pontes,Varolii, Pons,Varolius, Pons
D011930 Reaction Time The time from the onset of a stimulus until a response is observed. Response Latency,Response Speed,Response Time,Latency, Response,Reaction Times,Response Latencies,Response Times,Speed, Response,Speeds, Response
D011963 Receptors, GABA-A Cell surface proteins which bind GAMMA-AMINOBUTYRIC ACID and contain an integral membrane chloride channel. Each receptor is assembled as a pentamer from a pool of at least 19 different possible subunits. The receptors belong to a superfamily that share a common CYSTEINE loop. Benzodiazepine-Gaba Receptors,GABA-A Receptors,Receptors, Benzodiazepine,Receptors, Benzodiazepine-GABA,Receptors, Diazepam,Receptors, GABA-Benzodiazepine,Receptors, Muscimol,Benzodiazepine Receptor,Benzodiazepine Receptors,Benzodiazepine-GABA Receptor,Diazepam Receptor,Diazepam Receptors,GABA(A) Receptor,GABA-A Receptor,GABA-A Receptor alpha Subunit,GABA-A Receptor beta Subunit,GABA-A Receptor delta Subunit,GABA-A Receptor epsilon Subunit,GABA-A Receptor gamma Subunit,GABA-A Receptor rho Subunit,GABA-Benzodiazepine Receptor,GABA-Benzodiazepine Receptors,Muscimol Receptor,Muscimol Receptors,delta Subunit, GABA-A Receptor,epsilon Subunit, GABA-A Receptor,gamma-Aminobutyric Acid Subtype A Receptors,Benzodiazepine GABA Receptor,Benzodiazepine Gaba Receptors,GABA A Receptor,GABA A Receptor alpha Subunit,GABA A Receptor beta Subunit,GABA A Receptor delta Subunit,GABA A Receptor epsilon Subunit,GABA A Receptor gamma Subunit,GABA A Receptor rho Subunit,GABA A Receptors,GABA Benzodiazepine Receptor,GABA Benzodiazepine Receptors,Receptor, Benzodiazepine,Receptor, Benzodiazepine-GABA,Receptor, Diazepam,Receptor, GABA-A,Receptor, GABA-Benzodiazepine,Receptor, Muscimol,Receptors, Benzodiazepine GABA,Receptors, GABA A,Receptors, GABA Benzodiazepine,delta Subunit, GABA A Receptor,epsilon Subunit, GABA A Receptor,gamma Aminobutyric Acid Subtype A Receptors
D001931 Brain Mapping Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures. Brain Electrical Activity Mapping,Functional Cerebral Localization,Topographic Brain Mapping,Brain Mapping, Topographic,Functional Cerebral Localizations,Mapping, Brain,Mapping, Topographic Brain
D002685 Chiroptera Order of mammals whose members are adapted for flight. It includes bats, flying foxes, and fruit bats. Bats,Flying Foxes,Horseshoe Bats,Pteropodidae,Pteropus,Rhinolophus,Rousettus,Bat, Horseshoe,Bats, Horseshoe,Foxes, Flying,Horseshoe Bat
D004007 Dichotic Listening Tests Tests for central hearing disorders based on the competing message technique (binaural separation). Dichotic Listening Test,Listening Test, Dichotic,Listening Tests, Dichotic,Test, Dichotic Listening,Tests, Dichotic Listening

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