The distribution of the common inhibitory neuron in brachyuran limb musculature
In each of the seven muscles controlling the three distal joints of the walking legs ofEriphia, the common inhibitory neuron (CI) was found to innervate most strongly the slowly responding tonic fibers and least strongly or not at all the most rapidly responding phasic fibers.
Within each muscle, the fibers receiving CI occupy consistent locations as determined by electrophysiological mapping.
The distribution of four tonic through phasic fiber types was determined independently by histochemical means. The results agree closely with those obtained electrophysiologically.
In the muscles that receive two excitors in addition to CI (closer, bender, and extensor), a pronounced preferential distribution to tonic fibers was found both for CI and for the slow excitor. The fast excitor affects all fibers strongly; the most phasic fibers are innervated only by it.
In the opener and stretcher muscles, which each receive a specific inhibitor in addition to CI and a single shared excitor, all muscle fibers are innervated by the two inhibitors, although their efficacies differ. The specific inhibitor was found to affect all fibers strongly. CI's synaptic efficacy varies greatly: it exceeds that of the specific inhibitor in some tonic fibers, but is very weak (though always detectible) in the most phasic fibers. CI's effectiveness is similarly distributed in the singly excited and singly inhibited accessory flexor muscle.
In the flexor muscle with its quadruple excitatory innervation, CI and at least one particular excitatory axon again supply tonic fibers preferentially. At least one excitor appears to have a complementary distribution, innervating phasic but not tonic fibers.
KeywordsSpecific Inhibitor Fiber Type Preferential Distribution Limb Musculature Flexor Muscle
excitatory junctional potential
inhibitory junctional potential
Unable to display preview. Download preview PDF.
- Atwood HL (1973) Crustacean motor units. In: Stein RB, Pearson KG, Smith RS, Redford JB (eds) Control of posture and locomotion. Plenum Publishing Corporation, New York, pp 87–104Google Scholar
- Atwood HL, Bittner GD (1971) Matching of excitatory and inhibitory inputs to crustacean muscle fibers. J Neurophysiol 34:157–170Google Scholar
- Atwood HL, Parnas I, Wiersma CAG (1967) Inhibition in crustacean phasic neuromuscular systems. Comp Biochem Physiol 20:163–177Google Scholar
- Ballantyne D, Rathmayer W (1981) On the function of the common inhibitory neurone in the walking legs of the crab,Eriphia spinifrons. J Comp Physiol 143:111–122Google Scholar
- Bastiani MJ, Doe CQ, Helfand SL, Goodman CS (1985) Neuronal specificity and growth cone guidance in grasshopper andDrosophila embryos. Trends Neurosci 8:257–266Google Scholar
- Buller AJ, Eccles JC, Eccles RM (1960) Interactions between motoneurones and muscles in respect of the characteristic speed of their responses. J Physiol (Lond) 150:417–439Google Scholar
- Clarac F, Libersat F, Pflüger HJ, Rathmayer W (1987) Motor pattern analysis in the shore crab (Carcinus maenas) walking freely in water and on land. J Exp Biol 133:395–414Google Scholar
- Cohen MJ (1963) Muscle fibres and efferent nerves in a crustacean receptor muscle. Q J Microsc Sci 104:551–559Google Scholar
- Dorai Raj BS (1964) Diversity of crab muscle fibers innervated by a single motor axon. J Cell Comp Physiol 64:41–54Google Scholar
- Govind CK, Atwood HL (1982) Organization of neuromuscular systems. In: Atwood HL, Sandeman DC (eds) Neurobiology: Structure and function. vol. III, The biology of Crustacea. Academic Press, New York, pp 63–103Google Scholar
- Govind CK, Kent KS (1982) Transformation of fast fibres to slow prevented by lack of activity in developing lobster muscle. Nature 298:755–757Google Scholar
- Govind CK, Pearce J (1986) Differential reflex activity determines claw and closer muscle asymmetry in developing lobsters. Science 233:354–356Google Scholar
- Govind CK, Wiens TJ (1985) Innervation of the limb accessory flexor muscle in several decapod crustaceans. I. Anatomy. J Neurobiol 16:317–328Google Scholar
- Lnenicka GA, Atwood HL, Marin L (1986) Morphological transformation of synaptic terminals of a phasic motoneuron by long-term stimulation. J Neurosci 6:2252–2258Google Scholar
- Lømo T, Westgaard RH, Dahl HA (1974) Contractile properties of muscle: control by pattern of muscle activity in the rat. Proc R Soc Lond B 187:99–103Google Scholar
- Maier L, Rathmayer W, Pette D (1984) pH lability of myosin ATPase activity permits discrimination of different muscle fibre types in crustaceans. Histochemistry 81:75–77Google Scholar
- Maier L, Pette D, Rathmayer W (1986) Enzyme activities in single electrophysiologically identified crab muscle fibres. J Physiol (Lond) 371:191–199Google Scholar
- Parsons DW (1982) The leg flexor muscle ofCarcinus. I. Innervation and excitatory neuromuscular physiology. J Exp Zool 224:157–168Google Scholar
- Pette D (1984) Activity-induced fast to slow transitions in mammalian muscle. Med Sci Sports Exercise 16:517–528Google Scholar
- Pette D, Vrbova G (1985) Neural control of phenotypic expression in mammalian muscle fibers. Muscle and Nerve 8:676–689Google Scholar
- Rathmayer W, Erxleben C (1983) Identified muscle fibers in a crab. I. Characteristics of excitatory and inhibitory neuromuscular transmission. J Comp Physiol 152:411–420Google Scholar
- Rathmayer W, Hammelsbeck M (1985) Identified muscle fibres in a crab. Differences in facilitation properties. J Exp Biol 116:291–300Google Scholar
- Rathmayer W, Maier L (1987) Muscle fiber types in crabs: Studies on single identified muscle fibers. Am Zool 27:1067–1077Google Scholar
- Van Harreveld A, Wiersma CAG (1937) The triple innervation of crayfish muscle and its function in contraction and inhibition. J Exp Biol 14:448–461Google Scholar
- Wiens TJ, Atwood HL (1975) Dual inhibitory control in crab leg muscles. J Comp Physiol 99:211–230Google Scholar
- Wiens TJ, Govind CK (1985) Innervation of the limb accessory flexor muscle in several decapod crustaceans. II. Electrophysiology. J Neurobiol 16:349–359Google Scholar
- Wiens TJ, Rathmayer W (1985) The distribution of the common inhibitory neuron in brachyuran limb musculature. I. Target muscles. J Comp Physiol A 156:305–313Google Scholar
- Wiersma CAG (1941) The inhibitory nerve supply of the leg muscles of different decapod crustaceans. J Comp Neurol 74:63–79Google Scholar
- Wiersma CAG, Ripley SH (1952) Innervation patterns of crustacean limbs. Physiol Comp Oecol 2:391–405Google Scholar