Modulatory effects of noradrenaline on the spike activity of cat motor cortex neurons under conditions of skin electrostimulation and action of extra stimuli

Kniga, A. P.; Busel, B. I.

doi:10.1007/bf01054158

Cited by 1 publication

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“…These are an immediate synaptic effect on the target cell provided with the involvement of NA-ergic transmission and NA-ergic modulation of synaptic effects provided by other neurotransmitter(s). The effects of stimulation of the LC or of iontophoretic application of its specific neurotransmitter (NA), which are observed in various cortical regions, are rather heterogeneous; they can be either excitatory or inhibitory [20][21][22]. Mechanisms of NA-induced effects on the target neurons are rather complex.…”

Section: Resultsmentioning

confidence: 99%

Effects of Stimulation of the Periaqueductal Gray and Locus Coeruleus on Postsynaptic Reactions of Cat Somatosensory Cortex Neurons Activated by Nociceptors

et al. 2005

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In cats, we studied the influences of stimulation of the periaqueductal gray (PAG) and locus coeruleus (LC) on postsynaptic processes evoked in neurons of the somatosensory cortex by stimulation of nociceptive (intensive stimulation of the tooth pulp) and non-nociceptive (moderate stimulations of the infraorbital nerve and ventroposteromedial nucleus of the thalamus) afferent inputs. Twelve cells activated exclusively by nociceptors and 16 cells activated by both nociceptive and non-nociceptive influences (hereafter, nociceptive and convergent neurons, respectively) were recorded intracellularly. In neurons of both groups, responses to nociceptive stimulation (of sufficient intensity) looked like an EPSP-spike-IPSP (the latter, of significant duration, up to 200 msec) complex. Electrical stimulation of the PAG (which could itself evoke activation of the cortical neurons under study) resulted in long-term suppression of synaptic responses evoked by excitation of nociceptors (inhibition reached its maximum at a test interval of 600 to 800 msec). We observed a certain parallelism between conditioning influences of PAG activation and effects of systemic injections of morphine. Isolated stimulation of LC by a short high-frequency train of stimuli evoked primary excitatory responses (complex EPSPs) in a part of the examined cortical neurons, while in other cells high-amplitude and long-lasting IPSP (up to 120 msec) were observed. Independently of the type of the primary response to PAG stimulation, the latter resulted in long-term (several seconds) suppression of the responses evoked in cortical cells by stimulation of the nociceptive inputs. The mechanisms of modulatory influences coming from opioidergic and noradrenergic brain systems to somatosensory cortex neurons activated due to excitation of high-threshold (nociceptive) afferent inputs are discussed.

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Section: Resultsmentioning

confidence: 99%