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Substance P-like immunoreactivity in nerves associated with the vascular system of guinea-pigs
201
make conventional vide an anatomical transmission.
axosomatic and axodendritic substrate for opioid-induced
synapses. These observations propostsynaptic modulation of pain
Substance P-like immunoreactivity in nerves associated with the vascular system of guinea-pigs. - J.B. Furness, R.E. Papka, N.G. Della, M. Costa and R.L. Eskay, Neuroscience, 7 (1982) 447-459. All major blood vessels studied had an extensive network of axons containing substance-P like immunoreactivity. Very dense substance-P networks were found around the large elastic arteries close to the heart and in the arteries of the splanchnic bed. Significantly, arteries of the CNS were supplied with substance-P containing axons! The substance-P in blood vessels was depleted by treatment with capsaicin, indicating its origin from dorsal root ganglion cells. Dynorphin is a specific endogenous ligand of the K opioid receptor. - C. Chavkin, I.F. James and A. Goldstein, Science, 215 (1982) 413-415. The guinea pig ileum myenteric plexus preparation has mu and kappa but not delta opiate receptor. The action of mu agonists (e.g. morphine) is antagonized by naloxone, whereas the action of typical kappa agonists, such as ethylketocyclazocine (EKC) is not antagonized by naloxone. Dynorphin is a recently described 17 amino acid peptide which contains the leu-enkephalin sequence. In a competition binding assay, Dynorphin (1-13)-amide had a displacement pattern identical to EKC. Furthermore, Dynorphin (1-13) protected kappa binding sites from alkylation by the irreversible opiate receptor antagonist P-chlornaltrexamine. Finally, the biological effect of Dynorphin in the guinea pig ileum is only weakly antagonized by naloxone. The possibility that Dynorphin is the endogenous ligand for the kappa receptor is discussed.
PSYCHOLOGY Rate of stimulus repetition changes evoked potential amplitude: dental and auditory modalities compared. C.R. Chapman, Y.H. Colpitts, J.K. Mayeno and G.J. Gagliardi, Exp. Brain Res., 43 (1981) 246-252. Vertex event-related potentials (400-500 msec) elicited by painful dental stimulation have been shown to increase in amplitude with increments in stimulus intensity and pain. In this study such potentials were compared with those elicited by innocuous auditory stimuli across 3 rates of stimulus repetition: 1 set, 4 set and 8 sec. Stimulus intensity was held constant in both modalities. For both dental and auditory vertex ERPs peak amplitude of the major waveform components increased linearly over log rate as stimulus repetition was slowed, and latency of the latest positive component was increased. No changes in subjective stimulus intensity across rate of repetition were reported. These observations demonstrate that the normally close relationship between subjective pain report and ERP amplitude is not invariant, and they suggest that the development of ERP methodology in human pain research should proceed conservatively.
make conventional vide an anatomical transmission.
axosomatic and axodendritic substrate for opioid-induced
synapses. These observations propostsynaptic modulation of pain
Substance P-like immunoreactivity in nerves associated with the vascular system of guinea-pigs. - J.B. Furness, R.E. Papka, N.G. Della, M. Costa and R.L. Eskay, Neuroscience, 7 (1982) 447-459. All major blood vessels studied had an extensive network of axons containing substance-P like immunoreactivity. Very dense substance-P networks were found around the large elastic arteries close to the heart and in the arteries of the splanchnic bed. Significantly, arteries of the CNS were supplied with substance-P containing axons! The substance-P in blood vessels was depleted by treatment with capsaicin, indicating its origin from dorsal root ganglion cells. Dynorphin is a specific endogenous ligand of the K opioid receptor. - C. Chavkin, I.F. James and A. Goldstein, Science, 215 (1982) 413-415. The guinea pig ileum myenteric plexus preparation has mu and kappa but not delta opiate receptor. The action of mu agonists (e.g. morphine) is antagonized by naloxone, whereas the action of typical kappa agonists, such as ethylketocyclazocine (EKC) is not antagonized by naloxone. Dynorphin is a recently described 17 amino acid peptide which contains the leu-enkephalin sequence. In a competition binding assay, Dynorphin (1-13)-amide had a displacement pattern identical to EKC. Furthermore, Dynorphin (1-13) protected kappa binding sites from alkylation by the irreversible opiate receptor antagonist P-chlornaltrexamine. Finally, the biological effect of Dynorphin in the guinea pig ileum is only weakly antagonized by naloxone. The possibility that Dynorphin is the endogenous ligand for the kappa receptor is discussed.
PSYCHOLOGY Rate of stimulus repetition changes evoked potential amplitude: dental and auditory modalities compared. C.R. Chapman, Y.H. Colpitts, J.K. Mayeno and G.J. Gagliardi, Exp. Brain Res., 43 (1981) 246-252. Vertex event-related potentials (400-500 msec) elicited by painful dental stimulation have been shown to increase in amplitude with increments in stimulus intensity and pain. In this study such potentials were compared with those elicited by innocuous auditory stimuli across 3 rates of stimulus repetition: 1 set, 4 set and 8 sec. Stimulus intensity was held constant in both modalities. For both dental and auditory vertex ERPs peak amplitude of the major waveform components increased linearly over log rate as stimulus repetition was slowed, and latency of the latest positive component was increased. No changes in subjective stimulus intensity across rate of repetition were reported. These observations demonstrate that the normally close relationship between subjective pain report and ERP amplitude is not invariant, and they suggest that the development of ERP methodology in human pain research should proceed conservatively.