J Korean Acad Conserv Dent.  2005 Nov;30(6):470-476. 10.5395/JKACD.2005.30.6.470.

Regulation of pulpal microcirculation by calcitonin gene-related peptide

• Kim SK
• Kim YK
• Jin MU

• KMID: 2175753
• DOI: http://doi.org/10.5395/JKACD.2005.30.6.470

Abstract

The purpose of this study was to investigate the function of calcitonin gene-related peptide (CGRP) in regulatory mechanism of pulpal microcirculation with the aim of elucidating neurogenic inflammation. Experiments were performed on twelve cats under general anesthesia. CGRP was administered through the femoral vein to see the systemic influence and through the external carotid artery to see the local effect. Sympathetic nerve to the dental pulp was stimulated electrically and pulpal blood flow (PBF) was measured with a laser Doppler flowmeter on the canine teeth to the drug administration. The paired variables of control and experimental data were compared by paired t-test and differences with p < 0.05 were considered statistically significant. Systemic administration of CGRP (0.3 microg/kg) exerted decreases in systemic blood pressure and caused changes in PBF with an initial increase followed by decrease and a more marked second increase and decrease. Close intra-arterial (i.a.) injection of CGRP (0.03 microg/kg) resulted in slight PBF increase. The effect of CGRP resulted in no significant increase in PBF in the presence of CGRP8-37. The electrical stimulation of the sympathetic nerve alone resulted in PBF decreases. The i.a. administration of CGRP following the electrical stimulation of the sympathetic nerve compensated the decreased PBF. Therefore, CGRP effectively blocked the sympathetic nerve stimulation-induced PBF decrease.
Results
of the present study have provided evidences that even though the local vasodilatory function of CGRP are weak, CGRP is effectively involved in blocking the vasoconstriction caused by sympathetic nerve stimulation in the feline dental pulp.

Keyword

Dental pulp; Blood flow; Calcitonin gene related peptide (CGRP); Sympathetic nerve stimulation; Neurogenic inflammation; Laser Doppler flowmeter

MeSH Terms

Anesthesia, General
Animals
Blood Pressure
Calcitonin Gene-Related Peptide*
Calcitonin*
Carotid Artery, External
Cats
Cuspid
Dental Pulp
Electric Stimulation
Femoral Vein
Flowmeters
Microcirculation*
Neurogenic Inflammation
Vasoconstriction
Calcitonin
Calcitonin Gene-Related Peptide

Figure

• 

  Figure 1. Systemic influence of CGRP on pulpal blood flow (PBF, mean ± SEM). Injection of CGRP (0.3 μg/kg) through the femoral vein exerted decreases in systemic blood pressure and caused significant changes in PBF with 4 phases (p < 0.05).

• 

  Figure 2. (A) Polygraph recording showing the reduction of pulpal blood flow (PBF) during electrical stimulation of the sympathetic nerve (SNS). Systemic blood pressure did not change. (B) Polygraph recording showing the blocking effect of intra-arterial (i.a.) injection of CGRP (0.03 μg/kg) on SNS-induced PBF decrease.

• 

  Figure 3. Effect of CGRP alone and during the sympathetic nerve stimulation (SNS)-induced pulpal blood flow (PBF) reduction (mean ± SEM). Intra-arterial injection of CGRP (0.03 μg/kg) effectively recovered the reduced PBF caused by SNS (p < 0.05).

Reference

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