 |
The Journal of Neuroscience, February 18, 2004, 24(7):1744-1753; doi:10.1523/JNEUROSCI.4298-03.2004
Previous Article | Next Article 
Behavioral/Systems/Cognitive
Differential Effects of CB1 and Opioid Agonists on Two Populations of Adult Rat Dorsal Root Ganglion Neurons
I. A. Khasabova,1,2
C. Harding-Rose,2
D. A. Simone,2 and
V. S. Seybold1
Departments of 1Neuroscience and 2Oral Science, University of Minnesota, Minneapolis, Minnesota 55455
Inhibition of primary afferent neurons contributes to the antihyperalgesic effects of opioid and CB1 receptor agonists. Two bioassays were used to compare the effects of the CB1 receptor agonist CP 55,940 and morphine on dissociated adult rat DRG neurons. Both agonists inhibited the increase in free intracellular Ca2+ concentration evoked by depolarization; however, effects of CP 55,940 occurred primarily in large neurons (cell area, >800 µm2), whereas morphine inhibited the response in smaller neurons. Cotreatment with selective blockers of L-, N-, and P/Q-type voltage-dependent Ca2+ channels indicated that CB1 receptors on DRG neurons couple solely with N-type channels but opioid receptors couple with multiple subtypes. Experiments with selective agonists and antagonists of opioid receptors indicated that µ and , but not , receptors contributed to the inhibitory effect of morphine on voltage-dependent Ca2+ influx. Because Ca2+ channels underlie release of transmitters from neurons, the effects of opioid agonists and CP 55,940 on depolarization-evoked release of calcitonin gene-related peptide (CGRP) were compared. Morphine inhibited release through receptors but CP 55,940 had no effect. Colocalization of CGRP with -opioid but not µ-opioid or CB1 receptor immunoreactivity in superficial laminae of the dorsal horn of the spinal cord was consistent with the data for agonist inhibition of peptide release. Therefore, CB1 and opioid agonists couple with different voltage-dependent Ca2+ channels in different populations of DRG neurons. Furthermore, differences occur in the distribution of receptors between the cell body and terminals of DRG neurons. The complementary action of CB1 and opioid receptor agonists on populations of DRG neurons provides a rationale for their combined use in modulation of somatosensory input to the spinal cord.
Key words: opioid agonist; CB1 receptor; dorsal root ganglion; neuron; VDCC; CGRP
Received Sep 22, 2003;
revised December 12, 2003;
accepted December 16, 2003.
This article has been cited by other articles:

|
 |

|
 |
 
M. S. Riedl, P. D. Braun, K. F. Kitto, S. A. Roiko, L. B. Anderson, C. N. Honda, C. A. Fairbanks, and L. Vulchanova
Proteomic Analysis Uncovers Novel Actions of the Neurosecretory Protein VGF in Nociceptive Processing
J. Neurosci.,
October 21, 2009;
29(42):
13377 - 13388.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
M. Kano, T. Ohno-Shosaku, Y. Hashimotodani, M. Uchigashima, and M. Watanabe
Endocannabinoid-Mediated Control of Synaptic Transmission
Physiol Rev,
January 1, 2009;
89(1):
309 - 380.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
C. Potenzieri, T. S. Brink, C. Pacharinsak, and D. A. Simone
Cannabinoid Modulation of Cutaneous A{delta} Nociceptors During Inflammation
J Neurophysiol,
November 1, 2008;
100(5):
2794 - 2806.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
I. A. Khasabova, S. G. Khasabov, C. Harding-Rose, L. G. Coicou, B. A. Seybold, A. E. Lindberg, C. D. Steevens, D. A. Simone, and V. S. Seybold
A Decrease in Anandamide Signaling Contributes to the Maintenance of Cutaneous Mechanical Hyperalgesia in a Model of Bone Cancer Pain
J. Neurosci.,
October 29, 2008;
28(44):
11141 - 11152.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
P. W. Wacnik, K. M. Luhr, R. H. Hill, H.-G. Ljunggren, K. Kristensson, and M. Svensson
Cannabinoids Affect Dendritic Cell (DC) Potassium Channel Function and Modulate DC T Cell Stimulatory Capacity
J. Immunol.,
September 1, 2008;
181(5):
3057 - 3066.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. N. Akopian, N. B. Ruparel, A. Patwardhan, and K. M. Hargreaves
Cannabinoids Desensitize Capsaicin and Mustard Oil Responses in Sensory Neurons via TRPA1 Activation
J. Neurosci.,
January 30, 2008;
28(5):
1064 - 1075.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
N. A. Jeske, A. M. Patwardhan, N. Gamper, T. J. Price, A. N. Akopian, and K. M. Hargreaves
Cannabinoid WIN 55,212-2 Regulates TRPV1 Phosphorylation in Sensory Neurons
J. Biol. Chem.,
October 27, 2006;
281(43):
32879 - 32890.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
Y. Ji, A. Z. Murphy, and R. J. Traub
Sex differences in morphine-induced analgesia of visceral pain are supraspinally and peripherally mediated
Am J Physiol Regulatory Integrative Comp Physiol,
August 1, 2006;
291(2):
R307 - R314.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
H. N. Wenk, J.-D. Brederson, and C. N. Honda
Morphine Directly Inhibits Nociceptors in Inflamed Skin
J Neurophysiol,
April 1, 2006;
95(4):
2083 - 2097.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
L. M. Johanek and D. A. Simone
Cannabinoid Agonist, CP 55,940, Prevents Capsaicin-Induced Sensitization of Spinal Cord Dorsal Horn Neurons
J Neurophysiol,
February 1, 2005;
93(2):
989 - 997.
[Abstract]
[Full Text]
[PDF]
|
 |
|
|

|