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Differences in neurotransmitter systems of ventrolateral periaqueductal gray between the micturition reflex and nociceptive regulation: An in vivo microdialysis study
Author(s) -
Kitta Takeya,
Mitsui Takahiko,
Kanno Yukiko,
Chiba Hiroki,
Moriya Kimihiko,
Yoshioka Mitsuhiro,
Shinohara Nobuo
Publication year - 2016
Publication title -
international journal of urology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 67
eISSN - 1442-2042
pISSN - 0919-8172
DOI - 10.1111/iju.13096
Subject(s) - periaqueductal gray , urination , nociception , microdialysis , noxious stimulus , medicine , reflex , cystometry , glutamate receptor , stimulation , anesthesia , neuroscience , urinary bladder , central nervous system , endocrinology , urinary system , midbrain , biology , receptor
Objectives To elucidate the possible involvement of glutamate and serotonin (5‐hydroxytryptamine) neurons in the ventrolateral midbrain periaqueductal gray during noxious stimulation. Methods The study was carried out by evoking a noxious stimulation by acetic acid in an animal model of cystitis. Changes in glutamate and 5‐hydroxytryptamine in the periaqueductal gray during the micturition reflex and acetic acid‐induced cystitis were determined using in vivo microdialysis combined with cystometry in rats. Results Extracellular glutamate levels slightly, but significantly, increased during the micturition reflex induced by saline infusion into the bladder. Intravesical infusion of acetic acid facilitated the micturition reflex characterized by increases in voiding pressure and decreases in the intercontraction interval. Glutamate levels were markedly increased by acetic acid, and this enhancement was sustained for at least 3 h. 5‐Hydroxytryptamine levels, which were not altered during the micturition reflex, were increased after intravesical infusion of acetic acid. Conclusion The results suggest that periaqueductal gray glutamate and 5‐hydroxytryptamine neurons differentially participate in the modulation of both nociception and the micturition reflex. Furthermore, periaqueductal gray 5‐hydroxytryptamine levels appear to reflect the nociceptive stimuli.