Substance P content in the cerebrospinal fluid and fluid perfusing cerebral ventricles during elicitation and inhibition of trigemino-hypoglossal reflex in rats.
The aim of this study was to establish whether tooth pulp and periaqueductal central gray (PAG) stimulation affects the release of substance P (SP) into the fluid perfusing the cerebral ventricles in rats. The content of substance P in the cerebrospinal fluid and fluid perfusing cerebral ventricles was determined during incisor pulp stimulation with electrical impulses inducing nociceptive trigemino-hypoglossal reflex and then during inhibition of the reflex by stimulation of PAG. Perfusion of the cerebral ventricles was carried out using artificial cerebrospinal fluid (aCSF). SP-like immunoreactivity (SP-LI) was determined in the samples by radioimmunoassay. Samples were collected in four groups: first group-cerebrospinal fluid (CSF); second group-aCSF perfusates without stimulation; third group-aCSF perfusates during incisor pulp stimulation; fourth group-aCSF perfusates during incisor pulp stimulation and simultaneous inhibition of trigemino-hypoglossal reflex by PAG stimulation. It was shown that incisor pulp stimulation led to the increased release of SP-LI into the fluid perfusing cerebral ventricles. Stimulation of PAG reduced the release of SP-LI into the cerebro-ventricular system to the values obtained before the tooth pulp stimulation. The results indicate that PAG significantly inhibits the release of SP-LI into the rat cerebral ventricular system and may be involved in the inhibition of trigemino-hypoglossal reflex.
Zubrzycka
Maria
M
Department of Experimental and Clinical Physiology, Institute of Physiology and Biochemistry, Medical University, Mazowiecka 6/8, 92-215 Lódz, Poland. pawelska@polbox.com
Janecka
Anna
A
D000818:Animals; D002552:Cerebral Ventricles / Q000502:physiology; D003782:Dental Pulp / Q000294:innervation / Q000503:physiopathology; D004558:Electric Stimulation; D007002:Hypoglossal Nerve / Q000502:physiology; D008297:Male; D010487:Periaqueductal Gray / Q000503:physiopathology; D011863:Radioimmunoassay; D051381:Rats; D020318:Rats, Long-Evans; D012018:Reflex; D013373:Substance P / Q000134:cerebrospinal fluid* / Q000378:metabolism; D014276:Trigeminal Nerve / Q000502:physiology
D013373:Substance P