Presynaptic and post‐synaptic inhibition elicited in the cat's dorsal column nuclei by mechanical stimulation of skin

Andersen, P.; Etholm, B.; Gordon, G.

doi:10.1113/jphysiol.1970.sp009219

Cited by 70 publications

(31 citation statements)

References 16 publications

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“…Surround inhibition has also been described for neurones at other stages in the dorsal column system: in the dorsal column nuclei (Gordon & Jukes, 1964;Andersen, Etholm & Gordon, 1970;Bystrzycka, Nail & Rowe, 1977;Aoki, 1981); the thalamus (Poggio & Mountcastle, 1963;Gordon & Manson, 1967;Baker, 1971;Janig, Spencer & Younkin, 1979) and in the somatosensory cortex (Mountcastle & Powell, 1959;Baker, Tyner & Towe, 1971;Laskin & Spencer, 1979). It has generally been considered to provide a mechanism for improving spatial discrimination of tactile stimuli (Mountcastle & Powell, 1959;Gordon & Paine, 1960;Andersson, 1962).…”

Section: Discussionmentioning

confidence: 99%

Cutaneous excitatory and inhibitory input to neurones of the postsynaptic dorsal column system in the cat.

Noble

Riddell

1988

The Journal of Physiology

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SUMMARY1. In chloralose-anaesthetized cats single-unit microelectrode recordings were made from axons in the dorsal columns, at the lumbar level, identified as belonging to the postsynaptic dorsal column (PSDC) system.2. Excitatory and inhibitory receptive field arrangements of a sample of seventyfive PSDC neurones were examined in detail using natural cutaneous stimuli.3. The sample was characterized by a high degree of convergent input: 80% of units were activated by both light tactile and noxious mechanical stimuli and more than half of those examined were excited by noxious radiant heat. In addition, threequarters of the units had inhibitory receptive fields on the ipsilateral limb.4. Twenty-three units (27 %) were influenced by input from areas of both hairy and glabrous skin covering the foot and distal limb. Neurones in this group had complex receptive fields, many of which occupied several discontinuous areas of skin. Background and evoked activity of these units could frequently be inhibited by light tactile and/or noxious stimuli. Their inhibitory receptive fields occupied small areas of skin overlapping or adjacent to excitatory fields.5. Fifty-two units (73 %) had receptive fields restricted to areas of hairy skin on the thigh and upper hindlimb. Half the units in this group had coextensive low-and high-threshold excitatory areas but about one-third had a concentric receptive field organization; a high-threshold excitatory component extending beyond, or around, a central low-threshold area. The discharge of these units could be inhibited only by light tactile stimuli. Their inhibitory receptive fields covered extensive areas of skin, sometimes completely surrounding the excitatory field.6. The complex receptive field arrangements observed for neurones of the postsynaptic dorsal column system are discussed in relation to previous observations on dorsal horn neurones of other ascending tracts.

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Section: Discussionmentioning

confidence: 99%

Cutaneous excitatory and inhibitory input to neurones of the postsynaptic dorsal column system in the cat.

Noble

Riddell

1988

The Journal of Physiology

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“…An alternative explanation could involve the possibly different distributions of GABA receptors at pre-and post-synaptic sites in cuneate nucleus and cerebral cortex. Both pre-and post-synaptic inhibition have been demonstrated in the cuneate nucleus (Andersen, Etholm & Gordon, 1970) and GABA has been suggested as the transmitter for both mechanisms (Banna & Jabbur, 1969;Davidson & Reisine, 1971;Kelly & Renaud, 1971;Banna, Naccache & Jabbur, 1972;Kelly & Renaud, 1973c). In the cortex, however, only a post-synaptic action of GABA has been shown to occur, as yet (Krnjevic & Schwartz, 1968).…”

Section: Experimentalproceduresmentioning

confidence: 99%

Antagonism of Γ‐aminobutyric Acid and Glycine by Convulsants in the Cuneate Nucleus of Cat

Hill

Simmonds

Straughan

1976

British J Pharmacology

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1Some convulsant substances have been applied-to single neurones in the cat cuneate nucleus by microiontophoresis. Numerical values were derived for the effectiveness and selectivity of the substances as antagonists of y-aminobutyric acid (GABA) and glycine. 2 (+)-Bicuculline methochloride was the most effective GABA antagonist and it also excited many neurones. It antagonized GABA in 93% of experiments but also antagonized glycine in 41% of experiments. In most experiments the antagonism of GABA was greater than the antagonism of glycine resulting in an overall selective antagonism of GABA that was statistically significant. Nevertheless, in only about one quarter of the individual experiments was the GABA antagonism substantial and the selectivity clearcut. 3 (+)-Bicuculline and picrotoxin were less easily applied to neurones by microiontophoresis and were found to antagonize GABA in 30% and 35% of experiments, respectively. They also antagonized glycine in 25% and 30% of experiments, respectively. Overall, neither substance could be shown to be selective, statistically, although in the few individual experiments where the GABA antagonism was substantial the antagonism was clearly selective. 4 (+)Tubocurarine antagonized GABA in 59% and glycine in 32% of experiments and it also excited many neurones. Penicillin antagonized GABA in 33% of experiments without antagonizing glycine. Neither antagonist caused any substantial antagonisms of GABA and neither showed significant selectivity overall. (-)-Bicuculline methochloride, leptazol and bemegride antagonized GABA or glycine in less than 10% of experiments, although (-)-bicuculline methochloride excited most neurones. SStrychnine antagonized glycine in every experiment while antagonizing GABA in only 5% of experiments. In each individual experiment the antagonism of glycine was substantial and clearly selective, resulting in a statistically significant selectivity overall. 6 It is concluded that the selective glycine antagonist strychnine is considerably better than the presently available GABA antagonists for distinguishing between responses to GABA and glycine, when the antagonists are applied by microiontophoresis.

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“…This response was displayed on one beam of the oscilloscope while simultaneously the antidromic response evoked by the same test stimulus was displayed on the second beam. The first short-latency wave recorded in the medial lemniscus in response to stimulation of the cuneate nucleus is attributable to direct stimulation of cuneate neurones and axons (Andersen et al 1970). Alteration in the size of this response was therefore taken as reflecting alteration in the excitability of cuneate neurones.…”

Section: Methodsmentioning

confidence: 99%

Amino acids and presynaptic inhibition in the rat cuneate nucleus

Davidson¹,

Southwick²

1971

The Journal of Physiology

132

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SUMMARY1. Presynaptic inhibition was evoked in the rat cuneate nucleus by a peripheral conditioning stimulus. The dicarboxylic amino acid salts glutamate and aspartate and the neutral amino acids glycine and yaminobutyric acid (GABA) were topically applied to a restricted area of the cuneate nucleus and their effects on both resting primary afferent terminal excitability and the increase in excitability of afferent terminals during presynaptic inhibition determined.2. Aspartate had no effect on either resting primary afferent terminal excitability or on the increase in excitability during presynaptic inhibition.3. Glycine reduced both resting primary afferent terminal excitability and presynaptic inhibition.4. Glutamate increased both resting primary afferent terminal excitability and presynaptic inhibition while GABA increased resting primary afferent terminal excitability but reduced the increase in excitability during presynaptic inhibition.5. The convulsant alkaloids picrotoxin (given intravenously) and bicuculline (topically applied) blocked presynaptic inhibition. The blocking action of picrotoxin was overcome by topical application of GABA but not glutamate.6. Simultaneous measurement of pre-and post-synaptic excitability in the cuneate nucleus showed that while glutamate increased excitability at both sites, GABA increased primary afferent terminal excitability but depressed post-synaptic excitability.7. It is concluded that glycine and glutamate exert non-specific actions on primary afferent terminals similar to their effects at post-synaptic sites elsewhere in the c.N.s. while GABA depolarizes primary afferent terminals by a specific action at the same receptor site as the presynaptic inhibitory transmitter. The possibility is discussed that the presynaptic inhibitory transmitter in the cuneate nucleus is GABA or a closely related substance.

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Presynaptic and post‐synaptic inhibition elicited in the cat's dorsal column nuclei by mechanical stimulation of skin

Cited by 70 publications

References 16 publications

Cutaneous excitatory and inhibitory input to neurones of the postsynaptic dorsal column system in the cat.

Cutaneous excitatory and inhibitory input to neurones of the postsynaptic dorsal column system in the cat.

Antagonism of Γ‐aminobutyric Acid and Glycine by Convulsants in the Cuneate Nucleus of Cat

Amino acids and presynaptic inhibition in the rat cuneate nucleus

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