Substance P in the regulation of particle transport in the frog palate

Carmen J Hernandez Cruz de Arroyo, Fordham University

Abstract

The mucociliary transport system in the palate of Rana pipiens was investigated with a view toward finding a possible role of substance P comparable to that already described by others in the maxillary sinus of the rabbit. Studies were carried out on the rate of particle transport in anesthetized frogs, the ciliary beat frequency of cells in epithelial outgrowths of palate mucosa growing in culture, and on the immunocytological localization of substance P in the palatine nerve. Substance P-like immunoreactivity was found to be present in the axoplasm of nerve fibers in the palatine nerve suggesting the presence there of substance P or similar tachykinin. Exogenous substance P and acetylcholine accelerate mucociliary transport in the frog palate and ciliary beat frequency in outgrowths of palate epithelium. The effect of acetylcholine is blocked by atropine. The effect of substance P on particle transport is not blocked by atropine. The effect of exogenous substance P on particle transport is blocked by the substance P antagonist (D-Arg$\sp1$, D-Trp$\sp{7,9}$, Leu$\sp{11}$)SP. The block is reversible and does not involve muscarinic receptors. The effect of substance P on particle transport is mimicked by pharmacological activation of primary sensory fibers by capsaicin. The effect of capsaicin is blocked by the substance P antagonist (D-Arg$\sp1$, D-Trp$\sp{7,9}$, Leu$\sp{11}$)SP and by atropine. Electrical stimulation of the palatine nerve results in an increase of particle transport that is blocked partly by pretreatment with the substance P antagonist (D-Arg$\sp1$, D-Trp$\sp{7,9}$ Leu$\sp{11}$) SP and by atropine. The present data are consistent with the hypothesis that primary sensory fibers constitute the afferent component of a reflex arc. Stimulation of these fibers presumably releases substance P or similar tachykinin peripherally where it stimulates the epithelium directly, and centrally where it activates cholinergic effector neurons of the efferent pathway. The reflex probably involves connections at the brainstem. ^

Subject Area

Biology|Animal Physiology

Recommended Citation

Hernandez Cruz de Arroyo, Carmen J, "Substance P in the regulation of particle transport in the frog palate" (1990). ETD Collection for Fordham University. AAI9025020.
http://fordham.bepress.com/dissertations/AAI9025020

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