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Biomedical subjects

M Gautron

Publications and source records attributed to M Gautron.

43 records · Page 3Linked to original sources
PubMed1978

Negative effects of chronic hemicerebellectomy of epileptiform after-discharges elicited by focal cortical stimulation in baboons (Papio papio).

The influence of chronic hemicerebellectomy on cortical epileptiform after-discharge (AD) induced by focal electrical stimulation was studied in the baboon. These preliminary results include 22 ADs elicited from motor cortex and 22 ADs elicited from premotor cortex before and after hemicerebellectomy. Only full-developed, generalized seizures with postictal silence were considered. EEG morphology, average duration and average current threshold were compared for each set of ictal events. No significant differences were found before and after hemicerebellectomy.

Animals↗
PubMed1975

Afterdischarges elicited by electrical thalamic stimulation in the hemicerebellectomized baboon.

Electrical stimulation of the ventrolateral (VL) nucleus of the thalamus was performed on hemicerebellectomized baboons. Stimulation was delivered in volleys of 40 to 60 Hz lasting 5 to 25 sec, and at intensities ranging from 1 to 6 mA (width of shock 0.5 to 5 msec). Similar parameters of stimulation produced asymmetrical motor and electrocortical responses. When the normal VL nucleus was stimulated, these responses were tonic or tonic-clonic. When the VL nucleus deprived of its cerebellar afferents was stimulated, the tonic-clonic responses were followed by afterdischarges appearing in the EEG which persisted after cessation of stimulation. The role of the cerebellum in the lowering of the excitability threshold of some structures, particularly the VL nucleus, is discussed, as are the systems likely to play a role in producing various clinical responses.

Animals↗
PubMedDate not supplied

Effects of ES52, an enkephalinase inhibitor, on responses of ventrobasal thalamic neurons in rat.

The effects of ES52, a highly potent derivative of Thiorphan, an inhibitor of enkephalinase, at doses of 5 and 10 mg/kg IV were studied on the responses to cutaneous stimuli of 18 "nociceptive" (N), 10 "convergent" (NNn) and 4 "non-nociceptive" (Nn) neurons recorded in the ventrobasal (VB) complex of the rat. The responses of neurons exclusively driven by noxious mechanical and thermal stimuli (N neurons) were depressed by 56% by ES52 15 min after the injection of 5 or 10 mg/kg IV. This depressive effect was reversed by naloxone for half the neurons. For the ten neurons driven by both noxious and non-noxious stimuli (convergent NNn neurons), the responses to noxious heat were decreased by 42% at 15 min. By contrast, there was a marked enlargement of their receptive fields to light tactile stimuli, which was not naloxone-reversible. The receptive fields of neurons exclusively driven by non-noxious stimuli (Nn neurons) were also greatly expanded by ES52. These results show that ES52 can depress the responses of VB thalamic neurons to noxious stimuli; the effects on receptive field size underlines the complexity of the endogenous opiate systems.

Amino Acids, Sulfur↗