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Papers of the Week

Papers: 20 Apr 2019 - 26 Apr 2019

Animal Studies

2019 Jan-Dec

Mol Pain


Tachykinins modulate nociceptive responsiveness and sensitization: In vivo electrical characterization of primary sensory neurons in tachykinin knockout (Tac1 KO) mice.


Gutierrez S, Alvarado-Vasquez P A, Eisenach JC, Romero-Sandoval AE, Boada DM
Mol Pain. 2019 Jan-Dec; 15:1744806919845750.
PMID: 31012376.


Since the failure of specific substance P antagonists to induce analgesia, the role of tachykinins in the development of neuropathic pain states has been discounted. This conclusion was reached without studies on the role of tachykinins in normal patterns of primary afferents response and sensitization or the consequences of their absence on the modulation of primary mechano-nociceptive afferents after injury. Nociceptive afferents from animals lacking tachykinins (Tac1 knockout: KO) showed a disrupted pattern of activation to tonic suprathreshold mechanical stimulation. These nociceptors failed to encode the duration and magnitude of natural pronociceptive stimuli or to develop mechanical sensitization as consequence of this stimulation. Moreover, paw edema, hypersensitivity, and weight bearing were also reduced in Tac1 KO mice 24 hours after paw incision surgery. At this time, nociceptive afferents from these animals did not show the normal sensitization to mechanical stimulation or altered membrane electrical hyperexcitability as observed in wild type animals. These changes occurred despite a similar increase in CGRP immunoreactivity in sensory neurons in Tac1 KO and normal mice. Based on these observations we conclude that tachykinins are critical modulators of primary nociceptive afferents, with a preeminent role in the electrical control of their excitability with sustained activation or injury.