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Biomedical subjects

K M Zhang

Publications and source records attributed to K M Zhang.

24 records · Page 2Linked to original sources
PubMed1992

Release and depletion of substance P by capsaicin in substantia gelatinosa studied with the antibody microprobe technique and immunohistochemistry.

Using an antibody microprobe technique, we have detected substance P release from the region of the substantia gelatinosa of the cat during the first, but not the second, 30 min of topical application of capsaicin (1-3%) to the tibial nerve. Immunohistochemical analysis also showed that substance P-like immunoreactivity was markedly reduced in the superficial layer of the dorsal horn 30 min after application of capsaicin. These results indicate that substance P is released and then depleted from primary afferent central terminals following acute application of capsaicin to the peripheral sensory nerve.

Afferent Pathways↗
PubMed1992

[Inhibition of ohmefentanyl on articular afferent-induced responses of neurons in the spinal lamina X].

In 37 neurons of spinal lamina X, nociceptive responses were evoked by stimulation of the posterior articular nerve (PA) innervating the joint of hindlimb in anesthetized cats. Profound inhibition of nociceptive responses in 73.3% of neurons was induced by ohmefentanyl (1-2 micrograms.kg-1, iv), which was completely reversed by naloxone (80-330 micrograms.kg-1, iv). The results suggested that the mu-opioid receptors was involved in the regulation of transmission of nociceptive information in the spinal lamina X.

Analgesics↗
PubMed1990

Inhibition of nociceptive responses of dorsal horn neurones in the cat spinal cord by ohmefentanyl, a preferring mu opioid receptor agonist [corrected].

An action of ohmefentanyl (OMF), a novel preferring mu opioid receptor agonist, on nociceptive response of the dorsal horn neurone, has been studied in the spinal cat. OMF (0.5-2 micrograms/kg, i.v.) produced a potent naloxone-reversible inhibition of firing of dorsal horn neurones in response to noxious heating of glabrous hindpaw or to impulses in C primary afferents. When ejected into the substantia gelatinosa, OMF produced a relatively selective inhibition of C response, but not A response to excitation of myelinated afferent fibres, of the dorsal horn neurone. An interaction between ohmefentanyl and mu opioid receptors is discussed.

Action Potentials↗
PubMedDate not supplied

Effects of the calcium antagonist gallopamil on the increase of myocardial extracellular potassium activity during LAD occlusion in dogs.

It has been implied that the increase of myocardial extracellular potassium activity [( K+]e) in the early stage of acute myocardial ischemia is a major cause of the increased likelihood of arrhythmia after acute coronary artery occlusion. There is also experimental evidence that some calcium antagonists reduce the occurrence of ischemia-induced early ventricular arrhythmias. In order to clarify the antiarrhythmic effect of gallopamil during the early phase of acute LAD occlusion, the influence of this calcium antagonist on the time course of [K+]e during acute ischemia was measured in open-chest anesthetized dogs using a K+-selective surface multielectrode. The regional myocardial blood flow was determined with 9 micron radioactive tracer microspheres. After application of gallopamil (bolus 25 micrograms/kg and infusion 2.5 micrograms/kg.min for 30 min) the maximal and mean rate of rise of [K+]e as well as the plateau of [K+]e reached during ischemia were significantly diminished compared with the control occlusions. 90 min after gallopamil, the rate of rise of [K+]e as well as the plateau of [K+]e reached were still significantly reduced, but 180 min after the gallopamil application, no significant differences between the time course of [K+]e and that of the two control occlusions could be found. Gallopamil significantly elevated myocardial blood flow in the non-ischemic area, but did not influence blood flow in the ischemic region. While collateral perfusion remains unchanged, the slowed and reduced increase of myocardial [K+]e during acute coronary artery occlusion may be an important component of the antiarrhythmic effect of gallopamil during early ischemia.

Animals↗