Background: Intrathecal clonidine reduces tactile allodynia in animal models of neuropathic pain, and this effect is blocked by atropine. However, the role of tonic spinal cholinergic activity and its interaction with alpha2-adrenergic systems in normal and neuropathic conditions and to different sensory methods has not been systematically examined. The authors examined cholinergic receptor involvement in thermal and mechanical sensitivity in normal and neuropathic animals and its interaction with intrathecal clonidine.
Methods: Normal rats and rats that received L5/L6 spinal nerve ligation were tested with acute radiant heat, paw pressure, and punctate mechanical stimulation before and after the intrathecal administration of saline, the muscarinic receptor antagonist, atropine, or a toxin to destroy cholinergic neurons, and then after intrathecal clonidine.
Results: Atropine, the cholinergic neuronal toxin, and saline did not alter baseline withdrawal thresholds. In nerve-injured rats, neither saline nor atropine altered antinociception from clonidine to a thermal stimulus, but atropine reduced the effect of clonidine to von Frey filament withdrawal threshold (34 +/- 5.6 vs. 14 +/- 5.8 g [mean +/- SEM], saline vs. atropine; P < 0.05) and to withdrawal threshold to paw pressure after clonidine (174 +/- 18 g vs. 137 +/- 16 g, saline vs. atropine; P < 0.05).
Conclusions: These data suggest that after nerve injury, mechanical but not thermal antinociception from intrathecal clonidine relies on a muscarinic interaction, because only mechanical antinociception was antagonized by atropine. These results do not favor a regulation of nociceptive transmission by a tonic release of acetylcholine in nerve-injured rats.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1097/00000542-200307000-00030 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Indirect involvement of α-adrenoceptors in the mechanical antihypersensitivity effect induced by the spinally administered imidazoline I receptor ligand LNP599 in a rat model of experimental neuropathy.
Brain Res Bull
October 2024
Department of Physiology, Faculty of Medicine, University of Helsinki, Helsinki, Finland. Electronic address:
Here we assess whether neuropathic pain hypersensitivity is attenuated by spinal administration of the imidazoline I-receptor agonist LNP599 and whether the attenuation involves co-activation of α-adrenoceptors. Spared nerve injury (SNI) model of neuropathy was used to induce mechanical hypersensitivity in male and female rats with a chronic catheter for intrathecal drug administrations. Mechanical sensitivity and heat nociception were assessed behaviorally in the injured limb.
View Article and Find Full Text PDFComparison of the Effect of Scalp Block With Ropivacaine vs. Ropivacaine and Clonidine on Postoperative Pain in Patients Undergoing Craniotomy Surgery Under General Anesthesia.
Cureus
August 2024
Department of Anesthesiology, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Dr. D. Y. Patil Vidyapeeth, Pune, IND.
Article Synopsis
- - Clonidine, an α2 agonist, improves hypotensive and analgesic outcomes when added to scalp blocks during surgery, particularly enhancing ropivacaine's effectiveness for postoperative pain management.
- - A study involved 60 ASA grade I and II patients undergoing supratentorial craniotomy, divided into two groups: one receiving ropivacaine alone and the other receiving ropivacaine with clonidine.
- - Results showed that the combination of ropivacaine and clonidine significantly prolonged analgesia duration (9.10 hours vs. 4.30 hours) and reduced tramadol consumption compared to the ropivacaine-only group, with notable differences in blood pressure readings.
Thoracic spinal anesthesia with intrathecal sedation for lower back surgery: a retrospective cohort study.
Front Med (Lausanne)
April 2024
Department of Anesthesiology and Intensive Care, St. Ivan Rilski University Hospital, Sofia, Bulgaria.
Background: Spinal anesthesia (SA) is a good alternative to general anesthesia (GA) for spine surgery. Despite that, a few case series concern the use of thoracic spinal anesthesia for short-duration surgical interventions. In search of an alternative approach to GA and a better opioid-free modality, we aimed to investigate the safety, feasibility, and patient satisfaction of thoracic SA for spine surgery.
View Article and Find Full Text PDFCatheter Tip-Associated Mass With Continuous Infusion of Sufentanil for Persistent Spinal Pain Syndrome Type 2: A Case Report Including Histopathologic Examination and Review of the Associated Basic and Clinical Research.
Neuromodulation
October 2024
Department of Anesthesiology, University of California San Diego, San Diego, CA, USA. Electronic address:
Objectives: Intrathecal opioids delivered by implanted pumps are used to treat malignant or nonmalignant chronic pain. In this study, we 1) review a case in which intrathecal infusions of sufentanil along with other adjuvants were used and after an extended period led to an intrathecal mass and 2) compared and contrasted the potential mechanisms for these phenomena.
Materials And Methods: A woman aged 66 years with a history of scoliosis and multiple spine surgeries was treated with an implantable drug delivery system for treating persistent pain after laminectomy.
Dexmedetomidine Versus Clonidine as Additives for Spinal Anesthesia: A Comparative Study.
Anesth Pain Med
August 2023
Department of Anaesthesiology, Karpaga Vinayaga Institute of Medical Sciences and Research Centre, India.
Background: Postoperative pain management is vital to improve patient care. Successful postoperative pain relief is currently achieved only through NSAIDs and narcotics.
Objectives: We compared dexmedetomidine and clonidine as additives to hyperbaric levobupivicaine 0.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!