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β-Endorphin as a potent analgesic by intravenous injection
86 elicits a dose-dependent reflex f~l in blood pre,~sure. It is assumed that both a|gogens e x e ~ +~heir ~ffects by stimulating free paravascularly located sensory nerve ending,~ servir~g as pain receptors. Procaine and tetrodotox:h~ were used to investigate whether bradyki:nin and acetylcholine exe:cted their algesic effects ~Aa different types of nerve fibres. Procaine reduced the effects of bradykinin and acetylcholine to a very similar, degree. Tetrodotoxin reduced the effect of bradykinin slightly more ~han tha~ of acetylcholi~_e. it is concluded ~hat bradykinin and acetylcholine act via the same nerve fibres, but bradykinin seems to have some more affinity to fibres with a fewer number of s~divm channels than acetylcholine.
Substance P and analgesia J.M. Stewart, C.J. C-etto, K. Nelder, E.B. Reeve, W.A. Krivoy and E. Zimmermanp, Nature (Lond.), 262 (1976) 784--785 Substance P has long been known to have mm-ked effects on the central nervous system. It has been also suggested that substance P might be a transmitter of primary sensory impulses. Recent reports on the characterization of enkephalin suggested that enl:ephalin may be acting as an analogue of substance P. The mLthors have th~ refore examined substance P for morphinelike activity. The h ~,pothesis was ;,ested initially by examination of the effect by intracerebral in iection. Both substance P and morphine sulphate caused analgesia, evaluated by the imt plate method. The analgesia was prevented by naloxone. It was also shovm that mice trea$ed chronically with morphine did not show any analgesic reaction to morphine or substance P. Substance P injected intraperitoneally at dose levels of 5 n g and 1 pg per mouse also caused significant analgesia in mice. In view of these results the reported algogenic action of substance P on human blister base was reexamined using synthetic substance P. Synthetic substance P was not algogenic ut concentrations up to 1 mg/m', whereas acetylcholine and bradykinin were potent algo~ens. The previously reported algogenicity of substance P on the blister base may have been attributable to kinin contamination. The authors conclude that their experiments suggest that the development of a small peptide as a practical analgesic drug may be possible. ~-Endorphin as a p,l~tent analgesic by intravenous injection I,iang-Fu Tseng, H.H. Loh and Choh Hao Li, Nature (Lond.), 263 (1976) ~'39--240 An un~riakonta-pep~ide with significant, opiate activity from camel pituitar] glands was shown to have an amino acid sequence identical to the car-
~7 boxyl termine] 3!-amino acid of fl-iipotropins. The pep-~ide desigrmted as fiendorphin administered directly into the brain w~s feund to be considerably more potent than morphine in molar basis and its actions were blecked by naloxone. In the prese,at paper it is shown that ~-endorphin administered intravenously produced a dose-related inhibition of tail flick and hot plate response of mice to nociceptive ~timuli. These effects lasted 3 0 - 6 0 rain depending on the dose used and were prevented by naloxone. When the potency was compared on a molar basis fl-endorphin was 3--4 times more potent thar~ morphine.
MEDICINE
Prinzmetal's variant form of angina pectoris. Re-evaluation of mechanisms M. Endo, I. Kanda, S. Hosoda, H. Hayashi, K. Hirosawa and S. Konno, Circulation, 52 {1974) 33--37 A group of 35 patients with typical Prinzmetal's variant angina was examined. Coronary cineangiography did not demonstrate stenosis of the major coronary arteries in 19 patients. Nine patients with single coronary stenosis underwent aortocoronary bypass and had recurrence of pain postoperatively. Administration of nifedipine effected relief of pain both in patients not treated surgically and in patients previously treated surgically who had recurrence of pain postoperatively. These results suggest that neurohumoral factors exert more of an effect on the myocardial cell than on t h e coronary vessels and that neurohumoral control m a y play the greater part in causing the symptoms.
Uses of the electrical skin resistance method h-., the study of patients with neck and upper extremity pain L.H. Riley, Jr. and C.P. Richter, Johns Hopk. Med. J., 137 {1975) 69--74 Twenty patients with neck and upper extremity pain were examined: electrical skin resistance was mapped. In the patients examined there was no clinical or radiographic evidence of spinal cord or nerve root ir~'itation, but there was evidence of au abnormality within a cervical intervertebral disc or involving a i~acet joint of the cervical spine. Areas of low skin resistance (representing sympathetic hyperactiviLy), which correlated with tim patient's description c.f pain, were found over the neck in most patients. These results
Substance P and analgesia J.M. Stewart, C.J. C-etto, K. Nelder, E.B. Reeve, W.A. Krivoy and E. Zimmermanp, Nature (Lond.), 262 (1976) 784--785 Substance P has long been known to have mm-ked effects on the central nervous system. It has been also suggested that substance P might be a transmitter of primary sensory impulses. Recent reports on the characterization of enkephalin suggested that enl:ephalin may be acting as an analogue of substance P. The mLthors have th~ refore examined substance P for morphinelike activity. The h ~,pothesis was ;,ested initially by examination of the effect by intracerebral in iection. Both substance P and morphine sulphate caused analgesia, evaluated by the imt plate method. The analgesia was prevented by naloxone. It was also shovm that mice trea$ed chronically with morphine did not show any analgesic reaction to morphine or substance P. Substance P injected intraperitoneally at dose levels of 5 n g and 1 pg per mouse also caused significant analgesia in mice. In view of these results the reported algogenic action of substance P on human blister base was reexamined using synthetic substance P. Synthetic substance P was not algogenic ut concentrations up to 1 mg/m', whereas acetylcholine and bradykinin were potent algo~ens. The previously reported algogenicity of substance P on the blister base may have been attributable to kinin contamination. The authors conclude that their experiments suggest that the development of a small peptide as a practical analgesic drug may be possible. ~-Endorphin as a p,l~tent analgesic by intravenous injection I,iang-Fu Tseng, H.H. Loh and Choh Hao Li, Nature (Lond.), 263 (1976) ~'39--240 An un~riakonta-pep~ide with significant, opiate activity from camel pituitar] glands was shown to have an amino acid sequence identical to the car-
~7 boxyl termine] 3!-amino acid of fl-iipotropins. The pep-~ide desigrmted as fiendorphin administered directly into the brain w~s feund to be considerably more potent than morphine in molar basis and its actions were blecked by naloxone. In the prese,at paper it is shown that ~-endorphin administered intravenously produced a dose-related inhibition of tail flick and hot plate response of mice to nociceptive ~timuli. These effects lasted 3 0 - 6 0 rain depending on the dose used and were prevented by naloxone. When the potency was compared on a molar basis fl-endorphin was 3--4 times more potent thar~ morphine.
MEDICINE
Prinzmetal's variant form of angina pectoris. Re-evaluation of mechanisms M. Endo, I. Kanda, S. Hosoda, H. Hayashi, K. Hirosawa and S. Konno, Circulation, 52 {1974) 33--37 A group of 35 patients with typical Prinzmetal's variant angina was examined. Coronary cineangiography did not demonstrate stenosis of the major coronary arteries in 19 patients. Nine patients with single coronary stenosis underwent aortocoronary bypass and had recurrence of pain postoperatively. Administration of nifedipine effected relief of pain both in patients not treated surgically and in patients previously treated surgically who had recurrence of pain postoperatively. These results suggest that neurohumoral factors exert more of an effect on the myocardial cell than on t h e coronary vessels and that neurohumoral control m a y play the greater part in causing the symptoms.
Uses of the electrical skin resistance method h-., the study of patients with neck and upper extremity pain L.H. Riley, Jr. and C.P. Richter, Johns Hopk. Med. J., 137 {1975) 69--74 Twenty patients with neck and upper extremity pain were examined: electrical skin resistance was mapped. In the patients examined there was no clinical or radiographic evidence of spinal cord or nerve root ir~'itation, but there was evidence of au abnormality within a cervical intervertebral disc or involving a i~acet joint of the cervical spine. Areas of low skin resistance (representing sympathetic hyperactiviLy), which correlated with tim patient's description c.f pain, were found over the neck in most patients. These results