Electromyographic responses elicited by cutaneous and mixed nerve stimulation in human tibialis anterior muscle

The rectified and averaged myoelectrical responses of the anterior tibial muscle to stimulation of the posterior tibial, peroneal and sural nerves at the ankle were recorded during a weak isometric contraction in man. The stimulation of the posterior tibial nerve elicited two excitatory phases (short and long latency excitations) at 40 ms and 78 ms latencies, respectively, separated by a phase of reduced activity. With peroneal and sural nerve stimulation such triphasic responses were less consistent; only a monophasic inhibitory response occurred in some recordings. These results indicate that well-identifiable responses with distinct latencies can be obtained in human leg muscle with cutaneous and mixed nerve stimulation distal to the muscle.     

Electromyographic responses elicited by cutaneous and mixed nerve stimulation in human tibialis anterior muscle

Summary The rectified and averaged myoelectrical responses of the anterior tibial muscle to stimulation of the posterior tibial, peroneal and sural nerves at the ankle were recorded during a weak isometric contraction in man. The stimulation of the posterior tibial nerve elicited two excitatory phases (short and long latency excitations) at 40 ms and 78 ms latencies, respectively, separated by a phase of reduced activity. With peroneal and sural nerve stimulation such triphasic responses were less consistent; only a monophasic inhibitory response occurred in some recordings. These results indicate that well-identifiable responses with distinct latencies can be obtained in human leg muscle with cutaneous and mixed nerve stimulation distal to the muscle.This work was supported by the Council of Physical Education and Sport (Ministry of Education), Finland.     

Organization of reflex responses elicited in man by muscle stretch applied to uni- and bi-functional muscles]

The organization of human forearm reflexes following the application of extension torque perturbations has been studied in three flexors of the elbow: brachioradialis (BR), biceps (B), and pronator teres (PT). Two of these flexors are also involved in wrist supination: (B) and pronation (PT). During the perturbation, the wrist was fixed at various angles: from full supination to full pronation. The results show that the amplitude of the reflex responses of B and PT is highly dependent on wrist position. By eliminating biceps length changes as a source of observed reflex variation, it has been shown that the normalized reflex amplitude of B increases by 300% when the wrist position is varied from full pronation to full supination. In contrast, the BR muscle has a reflex response which is independent of wrist position. These results are discussed in relation to the role of reciprocal innervation and the possible action of receptors encoding wrist angle.     

Mechanical and biochemical characterization of the contraction elicited by a calcium-independent myosin light chain kinase in chemically skinned smooth muscle

Summary The contraction induced by a Ca²⁺-independent myosin light chain kinase (MLCK-) was characterized in terms of isometric force (F_o), immediate elastic recoil (SE), unloaded shortening velocity (V_us), shortening under a constant load and ATPase activity of chemically skinned smooth muscle preparations. These parameters were compared to those measured in a Ca²⁺-induced contraction to assess the nature of cross bridge interaction in the MLCK-induced contraction. F_o developed in chicken gizzard fibers as well as SE were similar in contractions elicited by either agent. V_us in the contraction induced by MLCK-(0.36 mg/ml) was similar though averaged 39.3±8.9% less than V_us induced by Ca²⁺ (1.6x10^–6M) in the control fibers. Addition of Ca²⁺ (1.6x10^–6M) to a contraction induced by MLCK-resulted in small increases in both F_o and V_us. Shortening under a constant load was similar for both types of contractions. The contraction induced by MLCK-was accompanied by an increased rate of ATP hydrolysis. The MLCK-induced contraction is thus kinetically similar though not identical to a contraction induced by Ca²⁺. We conclude that with respect to actin-myosin interaction, MLCK- and Ca²⁺-induced contractions are similar.     

Mechanical and biochemical characterization of the contraction elicited by a calcium-independent myosin light chain kinase in chemically skinned smooth muscle

The contraction induced by a Ca2+-independent myosin light chain kinase (MLCK-) was characterized in terms of isometric force (Fo), immediate elastic recoil (SE), unloaded shortening velocity (Vus), shortening under a constant load and ATPase activity of chemically skinned smooth muscle preparations. These parameters were compared to those measured in a Ca2+ -induced contraction to assess the nature of cross bridge interaction in the MLCK-induced contraction. Fo developed in chicken gizzard fibers as well as SE were similar in contractions elicited by either agent. Vus in the contraction induced by MLCK-(0.36 mg/ml) was similar though averaged 39.3 +/- 8.9% less than Vus induced by Ca2+ (1.6 X 10(-6) M) in the control fibers. Addition of Ca2+ (1.6 X 10(-6) M) to a contraction induced by MLCK-resulted in small increases in both Fo and Vus. Shortening under a constant load was similar for both types of contractions. The contraction induced by MLCK-was accompanied by an increased rate of ATP hydrolysis. The MLCK-induced contraction is thus kinetically similar though not identical to a contraction induced by Ca2+. We conclude that with respect to actin-myosin interaction, MLCK-and Ca2+ -induced contractions are similar.     

Opposite responses of muscle circulation to different emotional stimuli

Résumé La circulation musculaire du chat est influencée par les situations émotives: la vue d'un autre chat, agresseur, cause une vasoconstriction de nature adrénergique, tandis que la vue d'un chien cause une vasodilatation de nature cholinergique.

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On leave from the Department of Psychology, University of California, Los Angeles (California, USA).     

Feeding elicited in sheep by intrahypothalamic injections of PGE1

Résumé Une augmentation de la prise de nourriture a lieu après injection intrahypothalamique du PGE₁ en dose de 21 nmoles, chez les brebis. La température de la cavité abdominale n'est pas affectée par ces injections, sauf une légère augmentation au moment de l'injection et qui peut provenir du maniement des animaux.

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We are grateful to Dr.John E. Pike for the gift of PGE₁.

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This research was supported in part by a Grant-in-aid of the National Science Foundation, Grant No. GB-28836.     

Experimental hypertension elicited by injections of methyl cellulose

Résumé Des injections sous-cutanés d'une solution de méthyl-cellulose provoquent dans la rate une vraie hypertension artérielle maligne. Les animaux utilisés eurent fréquemment des dèmes et des ascites et toujours des lésions artérielles dans le cur, les reins et ailleurs.

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This study was supported by grants H-2703 and H-4327 from the United States Public Health Service.     

Attack elicited by forebrain and hypothalamic stimulation in the chicken

Zusammenfassung Elektrische Reizung begrenzter Stellen des medialen Archistriatums (Amygdala), Tractus occipito-mesencephalicus, Area septalis und des Hypothalamus vom Haushuhn, löst gezielten Angriff auf einen Artgenossen aus.     

Changes in Z-disc width of vertebrate skeletal muscle following tenotomy

Summary Results of unilateral Achilles tenotomy on male rats, after 2–6 weeks, showed conclusively that the Z-lines of tenotomized muscles are significantly wider than those of control, nontenotomized muscles.Acknowledgments. We would like to thank Paul Toselli, David Sack and Kathleen Finneran for their assistance with this project. This investigation was supported in part by NIH Grant No. HL 15462.     

Changes in lactic dehydrogenase isoenzyme pattern in muscle of tumor-bearing mice

Summary The lactic dehydrogenase isoenzyme distribution shifts gradually toward the isoenzyme pattern of the tumor in mouse muscles located distally from a transplanted mammary carcinoma.This study was supported by a grant from the Minnesota Masonic Memorial Cancer Research Fund and, in part, by Grant No. 16-P-5681015-17 from the Rehabilitation Services Administration, U.S. Dept. of Health, Education and Welfare.     

Changes in ascorbic acid content in denervated frog gastrocnemius muscle

Zusammenfassung Nach Denervierung des Gastrocnemius beim Frosch waren die Konzentrationen der l-Ascorbinsäure, Dehydro-l-Ascorbinsäure (DHA) und Diketoguloniksäure (DKA) im Nieren- und Nebennierengewebe unverändert. DHA und DKA fehlten, während ihre Konzentrationen in der Leber trotz Ascorbinsäurezunahme gleichmässig verteilt waren.     

Modifications in the type distribution of muscle fibers induced by repeated local freezings the rat sciatic nerve]

In the Rat, after a localized freezing of the sciatic nerve inducing a complete denervation of the medial head of the gastrocnemius muscle, the reinnervation took place within 16-18 days under our experimental conditions. After only one freezing, a limited and stable "type-grouping" of muscle fibres is observed from 30 to 360 days. After 2 to 5 freezing repeated every three weeks, the muscular changes observed one month after the last freezing are much more pronounced than when only one freezing is performed. These changes consist of a progressive increase in the number of type I and type II C fibres. This transformation is not stable: 3 months after the 3rd freezing, the muscle pattern does not differ from that which is noted after a single freezing.     

Cardiac muscle: Changes in optimal length during inotropic interventions

Résumé Des courbes exprimant le rapport longueurtension dans le muscle papillaire du chat furent étudiées en comparant des changements successifs de longueur. En traitant la préparation avec des substances inotropes, on produisit souvent des modifications marquées de la longueur optimale. Ces modifications peuvent avoir une importance dans la relation volume-pression du cur intact.

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This investigation was supported in part by a grant-in-aid from the American Heart Association, USPHS Research Grant No. HE 10282 from the National Heart Institute and a USPHS General Research Support Grant.     

Severe conditioned taste aversion elicited by venom of Russell's viper

Summary Conditioned taste aversion (CTA) established in rats by associating saccharin drinking with subsequent poisoning by Russell's viper venom. Retention test revealed 76 and 56% reduction of saccharin intake in venom and antivenom-venom groups. No CTA was observed in antivenom and control groups.This research was supported by Pakistan Science Foundation Islamabad. I am thankful to Dr J. Bure of Czechoslovakia, Academy of Sciences Prague for his guidance, comments and criticisms.     

Changes in total and polymerized tubulin of the medial basal hypothalamus and adenohypophysis of castrated or hormone-injected rats

Summary Treatment of orchidectomized rats with LH, FSH or prolactin decreased the tubulin content of the medial basal hypothalamus (MBH), whereas FSH or prolactin augmented it in the adenohypophysis (AH). After castration, negative correlations existed between serum LH and total or polymerized MBH tubulin, whereas in the AH positive correlations were found. After estradiol-progesterone treatment of spayed rats a significant correlation was found between serum LH and the percentage of AH tubulin in the polymerized form.Deceased November 24, 1979This study was supported in part by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas (CON-ICET), Argentina (grant n^o 6638) and a John Simon Guggenheim Memorial Foundation Fellowship to DPC.     

Local constriction and spasm of large arteries elicited by hypothalamic stimulation

Zusammenfassung Die nervöse Kontrolle der Femoral-, Brachial-, zentralen Ohr- und Mesenterialarterien wurde am Kaninchen untersucht. Es konnten durch elektrische Reizung eines Gebietes im lateralen Hypothalamus abgestufte Gefässverengerungen hervorgerufen werden. Ohne wesentliche Änderung des Aortenmitteldruckes und der Herzfrequenz konnten sogar maximale Kontraktionen hervorgerufen werden. Lange Reize verursachten anhaltenden Gefässspasmus, der in der A. femoralis am stärksten ausgeprägt war.     

Inhibition of ovarian compensatory hypertrophy by implants of atropine in the hypothalamus

Résumé Des injections d'atropine dans l'hypothalamus antérieur et latéral de la rate font disparaître l'hypertrophie compensatrice de l'ovaire qui suit l'hémicastration. On conclut que dans ces conditions, l'atropine agit par des voies cholinergiques en relation avec la sécrétion des gonadotrophines.