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Titolo:
TRICEPS SURAE MOTONEURON MORPHOLOGY IN THE RAT - A QUANTITATIVE LIGHT-MICROSCOPIC STUDY
Autore:
CHEN XY; WOLPAW JR;
Indirizzi:
NEW YORK STATE DEPT HLTH,WADSWORTH CTR LABS & RES,POB 509,EMPIRE STATE PLAZA ALBANY NY 12201 SUNY ALBANY ALBANY NY 12201
Titolo Testata:
Journal of comparative neurology
fascicolo: 1, volume: 343, anno: 1994,
pagine: 143 - 157
SICI:
0021-9967(1994)343:1<143:TSMMIT>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
DENDRITIC GROWTH CONES; HORSERADISH-PEROXIDASE; ALPHA-MOTONEURONS; MOTO-NEURONS; SPINAL-CORD; GAMMA-MOTONEURONS; CAT; SIZE; HRP; ORGANIZATION;
Keywords:
DENDRITES; HORSERADISH PEROXIDASE; IMAGE PROCESSING; COMPUTER ASSISTED; SOFTWARE; SPINAL CORD;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
58
Recensione:
Indirizzi per estratti:
Citazione:
X.Y. Chen e J.R. Wolpaw, "TRICEPS SURAE MOTONEURON MORPHOLOGY IN THE RAT - A QUANTITATIVE LIGHT-MICROSCOPIC STUDY", Journal of comparative neurology, 343(1), 1994, pp. 143-157

Abstract

The rat is now the model of choice for many studies of motor function. However, little quantitative information on the structure of rat motoneurons is available. In conjunction with efforts to define the physiologic and anatomic substrates of operantly conditioned plasticity in the spinal cord, 13 physiologically identified triceps surae motoneurons in the rat lumbar spinal cord were labeled intracellularly with horseradish peroxidase and completely reconstructed and measured with a computer-based neuron-tracing system. Somata were all located in the ventral horn of lumbar segments 4-5, had an average diameter of 35 mu m,and had 6-12 dendrites. Dendrites ramified throughout the ventral horn and also penetrated the white matter. Their spread was greater in the rostrocaudal and dorsoventral directions (1.53 +/- 0.24 mm and 1.35 /- 0.23 mm, respectively) than in the mediolateral direction (0.85 +/- 0.14 mm). Regardless of soma location, dendritic fields usually extended throughout the ipsilateral coronal cross-section of the ventral horn. As a result, the ventral or lateral extent of the field was correlated strongly with the soma's distance from the ventral or lateral border, respectively, of the ventral horn. Furthermore, although soma locations in the coronal plane varied widely, the centers of the dendritic fields tended to cluster near the center of the ventral horn. Dendrites constituted 96.2-98.4% (mean +/- SD = 97.3 +/- 0.7%) of the totalneuronal surface area. Each of the 104 dendrites studied had an average of 13 branch points and 27 segments. First-order segment diameters ranged from 1.4 to 11.7 mu m (mean +/- SD = 5.3 +/- 2.1 mu m) Total dendritic length, surface area, volume, number of dendritic segments, and maximum segment order were correlated strongly with diameter of the first-order segment. Proceeding distally between branch points, the mean decrease in dendritic diameter (i.e., tapering) +/- the standard deviation was 22 +/- 8% of the proximal diameter. The average ratio +/- the standard deviation of the sum of the average diameters of each daughter segment raised to the 1.5 power to the average diameter of the parent segment raised to the 1.5 power (i.e., Rall's ratio; Rall, 1959)was 0.87 +/- 0.08. In comparison with cat alpha-motoneurons, rat motoneurons had smaller soma diameters, fewer dendrites, smaller total surface areas, and shorter total dendritic lengths. However, the number of terminations per dendrite was similar in the two species, so that rat motoneurons had more terminations per unit dendritic length. This greater branching density indicates that the dendritic fields of rat motoneurons are more compact and their branching structures are more densely packed than those of cat motoneurons. (C) 1994 Wiley-Liss, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/09/20 alle ore 18:15:04