Nerve growth factor with fibrin glue in end-to-side nerve repair in rats / Fator de crescimento nervoso em cola de fibrina no reparo término-lateral de nervos em ratos

PURPOSE: To determine the effects of end-to-side nerve repair performed only with fibrin glue containing nerve growth in rats. METHODS: Seventy two Wistar rats were divided into six equal groups: group A was not submitted to nerve section; group B was submitted to nerve fibular section only. The others groups had the nerve fibular sectioned and then repaired in the lateral surface of an intact tibial nerve, with different procedures: group C: ETS with sutures; group D: ETS with sutures and NGF; group E: ETS with FG only; group F: ETS with FG containing NGF. The motor function was accompanied and the tibial muscle mass, the number and diameter of muscular fibers and regenerated axons were measured. RESULTS: All the analyzed variables did not show any differences among the four operated groups (p>0.05), which were statistically superior to group B (p<0.05), but inferior to group A (p>0.05). CONCLUSION: The end-to-side nerve repair presented the same recovery pattern, independent from the repair used, showing that the addition of nerve growth factor in fibrin glue was not enough for the results potentiating.

OBJETIVO: Determinar os efeitos do reparo nervoso término-lateral realizado apenas com cola de fibrina contendo fator de crescimento nervoso em ratos. MÉTODOS: Setenta e dois ratos Wistar foram distribuídos em seis grupos: A - não submetido à secção nervosa; B - secção do nervo fibular (sem reparo); Os outros grupos tiveram o nervo fibular seccionado e então reparado na superfície lateral do nervo tibial intacto, com diferentes procedimentos: C - RNTL com suturas; D - RNTL com suturas e FCN; E - RNTL apenas com CF; F - RNTL com CF contendo FCN. A função motora foi acompanhada e a massa do músculo tibial, o número e o diâmetro das fibras musculares e axônios regenerados foram medidos. RESULTADOS: Não houve diferença entre as variáveis avaliadas nos quatro grupos operados (p>0,05), os quais foram superiores ao grupo B (p<0,05), mas inferiores ao grupo A (p>0,05). CONCLUSÕES: O reparo nervoso término-lateral mostrou o mesmo padrão de recuperação, independente do tipo de reparo utilizado, evidenciando que a adição de fator de crescimento nervoso na cola de fibrina não foi suficiente para a potencialização dos resultados.

Important recent advances in cardiovascular adrenergic mechanisms

Five sub-areas were taken into consideration: Adrenoceptor subclassification: Presently, 10 different adrenoceptor subtypes have been characterized by pharmacological and molecular biology studies: Ó1A-, Ó1B-, Ó1D-, Ó2A/D, Ó2B-, Ó2C-, ß1-, ß2-, ß3- and ß4-adrenoceptors. Intracellular signaling: the adrenoceptors are members of a large superfamily of receptors linked to guanine-nucleotide proteins (G proteins), Ó1-adrenoceptors are coupled to Gq proteins and activate phospholipases, especially phospholipase Cß, Ó2-adrenoceptors are coupled to G1 proteins and inhibit adenylyl cyclase and in some tissues regulate potassium and calcium channels. Both ß1 and ß2-adrenoceptors are preferentially coupled to adenylyl cyclase through GS proteins and ß3-adrenoceptors appear to be coupled to K+ channel through a pertussis toxin-sensitive G1 protein. ß4-Adrenoceptors appear to be coupled positively to a cyclic AMP-dependent cascade and can undergo desensitization. Influence of maturation and ageing: From birth to old age important changes occur in animal models as in humans at the receptor level, neurotransmitter process and catecholamine disposition. In general terms, one can say that maturation is associated with a gradual increase of adrenergic influence, while ageing is associated with a reduction in the role of the adrenergic system on the regulation of physiologic processes. Cotransmission: ATP and the neuropeptide Y are cotransmitters with noradrenaline. While noradrenaline is the main transmitter in vascular tissues, ATP has functional relevance in some vessels and neuropeptide Y is mainly a modulator of noradrenaline release; it seems that it has an increased role under pathophysiological conditions like ischemia. Role of endothelium on noradrenaline release: Many substances produced by the endotelium or acting through the endothelium are able to influence noradrenaline release from sympathetic nerve varicosities of the blood vessel wall: some of them, like bradykinin and angiotensin II, exert a facilitatory, while others like NO and endothelin have an inhibitory effect on noradrenaline release evoked electrical nerve stimulation.

Non-linear correlation between nerve terminal parameters and muscle fibre diameter of exercised mice during aging

The effect of exercise on morphological age changes in endplate parameters and their relation to muscle fibre diameter was studied in male [C57B1/6J] mice. Animals [N = 60; half of them served as controls] aged 12, 18 and 24 months at sacrifice, were treadmill exercised for two months for 1 h/day at velocities up to 30 m/min. The area [A], perimeter [P], nerve longitudinal extent length [E] and fibre diameter [FD] from camera lucida drawings of extensor digitorum longus zinc iodide osmium-stained nerve terminals were measured. Non-linear regression and multivariate analysis were used to study the inter-relationships among these parameters under aging and exercise conditions. At 12 months E was strongly correlated with FD, but the correlation badly deteriorated with aging, and exercise did not improve it. At all ages A was not correlated with FD during aging alone, but with exercise the correlation improved, especially at 18 months [r2 = 0.73]. The ratio E/FD was not correlated with the other endplate parameters except in exercised animals, in whom E/FD showed a high correlation with A, especially at age 12 months [r2 = 0.72]. FD showed a high correlation with P/A at 12 months of age, but exercise decreased this correlation at all ages. Multivariate analysis showed no significant relationship between FD and nerve terminal parameters at any age in control animals, but in exercised animals a close relationship appeared, given by the equation: FD = 18.75 + 0.025A - 0.08E + 0.01P with P < 0.01 and r2 = 0.34. The discovery of a non-linear relationship between FD and nerve terminal parameters makes possible a further analysis of the effects of exercise on morphological age changes at the neuromuscular junction

Inervaçäo autônoma do útero de mamíferos / Autonomic Innervation of the mammalian uterus

Apresenta-se uma revisäo sobre a inervaçäo autônoma do útero de mamíferos.

A review on drugs and toxins affecting presynaptic K+ currents and phasic quantal transmitter release at motor nerve terminals

Esta revisión reúne la información disponible sobre los agentes farmacológicos y toxina sque bloquean los diferentes tipos de corrientes de K+ presinápticas, y discute la importancia relativa de estas corrientes en el control de la liberación fásica y cuántica del transmisor. Los agentes farmacológicos y toxinas que bloquean la corriente rápida de K+ voltaje-dependiente (IKf), aumentan la liberación fásica de actilcolina evocada por el impulso nervioso. Este efecto es debido al aumento del influjo de Ca2+ durante la despolarización de la membrana presináptica. El bloqueo selectivo de la correinte de K+ calcio-dependiente IK(Ca) no produce ningún cambio en la liberación fásica del transmisor, lo cual indica que en condiciones fisiológicas esta corriente no tiene un papel significaivo en la repolarización de la membrana presináptica. La contribución de la corriente lenta de K+ voltaje-dependiente (IKs) en la liberación fásica de acetilcolina no ha sido aún dilucidada. En conclusión, IKf, IK(Ca) e IKs pueden modular la entrada de Ca2ñ en las terminaciones nerviosas motoras; sin embargo, en condiciones fisiológicas solamente IKf tiene una importancia clave, ya que controla el indlujo transitorio de Ca2+ que es responsable d ela liberación fásica del neurotransmisor

The Physiological Significance of Natural Mechanical Stimulus in the Field of Cerebrospinal Nervous System

Full evidence and obvious reasons made it possible to arrive at the conclusion that the nature of transmission upon cerebrospinal neurons is overwhelmingly mechanical, not only in the periphery- between various receptors and afferent nerve terminals, and between surrounding tissues and free nerve endings- but also in the cerebral cortex. When viewed from the standpoint of the everchanging patterns of natural mechanical stimuli, the neurons in the conscious cerebral cortex and the pain endings in an acute inflammatory locus have the same situation very much in common. It is quite likely that natural mechanical stimuli dominate over cerebrospinal nervous phenomena and physiologists have been watching the missing mechanism at work in every experiment upon afferent nerve terminals and cerebral cortex that they have done. The terms "psychic tension" and "central excitatory state" comparable to muscular tonus are of interest because they involve the use of mathematical techniques in psychology and neurophysiology. They are capable of becoming weak or strong, and they serve as an inner stimulus to give impetus to behavior. Unfortunately, however, it is an elusive inner stimulus, and it defies a lucid definition. But natural mechanical stimuli embody the psychic tension and the central excitatory state ultimately. It seems now that we just found a place where constant complaints against neurophysiology and physiological psychology are ventilated. We may conclude that natural mechanical stimuli are the leading direct stimuli to cerebrospinal neurons in the human body, and the plastic and developmental nervous phenomena and mental phenomena can be explained objectively by a familliar datum of mechanical energy and that we can reasonably expect the day of regarding material world and spiritual world in the monistic conception of matter-energy system.