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Biomedical subjects

G Leng

Publications and source records attributed to G Leng.

8 recordsLinked to original sources
PubMed1992

Mechanisms of vasopressin secretion.

The magnocellular vasopressin system of the rat has been studied intensively in recent years. This review outlines the electrophysiological characteristics of vasopressin neurons, the characteristics of stimulus-secretion coupling in the neural lobe, and describes some of the major features of the neural regulation of this system which underlie physiological regulation of vasopressin release by osmoregulatory stimuli. The major afferent pathways to the magnocellular system are now well characterised. Those involved in osmoregulation have been mapped using expression of the primary response gene c-fos as a marker for neuronal activation.

Afferent Pathways↗
PubMed1979

Effects of increased potassium in scala tympani on auditory nerve sensitivity.

Raising the K+ concentration in scala tympani of the guinea-pig cochlea generally caused a substantial increase in the spontaneous firing rate of single auditory nerve fibres. This effect was not accompanied by any observed reduction in the threshold sensitivity of these fibres. These findings cast doubt on current theories of cochlear transduction.

Action Potentials↗
PubMed1979

Action of putative neurotransmitters in the guinea pig cochlea.

Scala tympani of the guinea pig was perfused with artificial perilymph containing putative transmitter substances. Single auditory nerve fibre activity was recorded during these perfusions and the responses of these fibres were studied using computer-controlled routine. Acetylcholine significantly inhibited tone-induced responses of a large proportion of the fibres tested. Glutamate appeared to be a potent depolarising agent when applied in concentrations between 2 and 10 mM. Noradrenaline did not affect tone-induced activity, but inhibited the spontaneous activity of some fibres. The results support the view that acetylcholine is the transmitter at synapses of the olivocochlear bundle, and that glutamate may be involved in the afferent synapse. The data do not support the hypothesis that noradrenaline is the afferent transmitter.

Acetylcholine↗
PubMedDate not supplied

The effect of potassium on the activity of auditory nerve fibres of the guinea pig cochlea.

Scala tympani of the guinea pig cochlea was perfused with solutions having an increased potassium concentration. The response characteristics of single auditory nerve fibres in both normal and kanamycin-damaged cochleas were studied using computer controlled routines. The results indicate that these perfusions caused a marked increase in the spontaneous firing rate of auditory nerve fibres, without loss of threshold sensitivity. Current theories of cochlear transduction support the view that the potassium concentration difference across the reticular plate is fundamental to the sensitivity of the cochlea. The results presented here do not support this view.

Acoustic Stimulation↗