Effects of noradrenaline on locomotor rhythm-generating networks in the isolated neonatal rat spinal cord

被引:89
作者
Kiehn, O
Sillar, KT
Kjaerulff, O
McDearmid, JR
机构
[1] Univ Copenhagen, Panum Inst, Dept Physiol, Sect Neurophysiol, DK-2200 Copenhagen N, Denmark
[2] Univ St Andrews, Sch Biomed Sci, Gatty Marine Lab, St Andrews KY10 3SS, Fife, Scotland
基金
英国惠康基金;
关键词
D O I
10.1152/jn.1999.82.2.741
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
We have studied the effects of the biogenic amine noradrenaline (NA) on motor activity in the isolated neonatal rat spinal cord. The motor output was recorded with suction electrodes from the lumbar ventral roots. When applied on its own, NA (0.5-50 mu M) elicited either no measurable root activity, or activity of a highly variable nature. When present, the NA-induced activity consisted of either low levels of unpatterned tonic discharges, or an often irregular, slow rhythm that displayed a high degree of synchrony between antagonistic motor pools. Finally, in a few cases, NA induced a slow locomotor-like rhythm, in which activity alternated between the left and right sides, and between rostral and caudal roots on the same side. As shown previously, stable locomotor activity could be induced by bath application of N-methyl-D-aspartate (NMDA; 4-8.5 mu M) and/or serotonin (5-HT; 4-20 mu M). NA modulated this activity by decreasing the cycle frequency and increasing the ventral root burst duration. These effects were dose dependent in the concentration range 1-5 mu M. In contrast. at no concentration tested did NA have consistent effects on burst amplitudes or on the background activity of the ongoing rhythm, Moreover, NA did not obviously affect the left/right and rostrocaudal alternation of the NMDA/5-HT rhythm. The NMDA/5-HT locomotor rhythm sometimes displayed a time-dependent breakdown in coordination, ultimately resulting in tonic ventral root activity. However, the addition of NA to the NMDA/5-HT saline could reinstate a well-coordinated locomotor rhythm. We conclude that exogenously applied NA can elicit tonic activity or can trigger a slow, irregular and often synchronous motor pattern. When NA is applied during ongoing locomotor activity, the amine has a distinct slowing effect on the rhythm while preserving the normal coordination between flexors and extensors. The ability of NA to "rescue" rhythmic locomotor activity after its time-dependent deterioration suggests that the amine may be important in the maintenance of rhythmic motor activity.
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页码:741 / 746
页数:6
相关论文
共 28 条
[1]   INITIATION AND MODULATION OF THE LOCOMOTOR PATTERN IN THE ADULT CHRONIC SPINAL CAT BY NORADRENERGIC, SEROTONERGIC AND DOPAMINERGIC DRUGS [J].
BARBEAU, H ;
ROSSIGNOL, S .
BRAIN RESEARCH, 1991, 546 (02) :250-260
[2]  
Bracci E, 1996, J NEUROSCI, V16, P7063
[3]   2 TYPES OF MOTOR RHYTHM INDUCED BY NMDA AND AMINES IN AN INVITRO SPINAL-CORD PREPARATION OF NEONATAL RAT [J].
CAZALETS, JR ;
GRILLNER, P ;
MENARD, I ;
CREMIEUX, J ;
CLARAC, F .
NEUROSCIENCE LETTERS, 1990, 111 (1-2) :116-121
[4]   ACTIVATION OF THE CENTRAL PATTERN GENERATORS FOR LOCOMOTION BY SEROTONIN AND EXCITATORY AMINO-ACIDS IN NEONATAL RAT [J].
CAZALETS, JR ;
SQALLIHOUSSAINI, Y ;
CLARAC, F .
JOURNAL OF PHYSIOLOGY-LONDON, 1992, 455 :187-204
[5]   Effects of intrathecal α1- and α2-noradrenergic agonists and norepinephrine on locomotion in chronic spinal cats [J].
Chau, C ;
Barbeau, H ;
Rossignol, S .
JOURNAL OF NEUROPHYSIOLOGY, 1998, 79 (06) :2941-2963
[6]   EFFECTS OF INHIBITORY AMINO-ACID ANTAGONISTS ON RECIPROCAL INHIBITORY INTERACTIONS DURING RHYTHMIC MOTOR-ACTIVITY IN THE IN-VITRO NEONATAL RAT SPINAL-CORD [J].
COWLEY, KC ;
SCHMIDT, BJ .
JOURNAL OF NEUROPHYSIOLOGY, 1995, 74 (03) :1109-1117
[7]   A COMPARISON OF MOTOR PATTERNS INDUCED BY N-METHYL-D-ASPARTATE, ACETYLCHOLINE AND SEROTONIN IN THE IN-VITRO NEONATAL RAT SPINAL-CORD [J].
COWLEY, KC ;
SCHMIDT, BJ .
NEUROSCIENCE LETTERS, 1994, 171 (1-2) :147-150
[8]   LOCOMOTION OF ACUTE SPINAL CAT INJECTED WITH CLONIDINE IV [J].
FORSSBERG, H ;
GRILLNER, S .
BRAIN RESEARCH, 1973, 50 (01) :184-186
[9]  
GRILLNER S, 1979, EXP BRAIN RES, V34, P241
[10]  
HARRISWARRICK RM, 1985, J EXP BIOL, V116, P27