The effects of prenatal capsaicin on the distribution of substance P in developing primary afferent neurons.
Capsaicin was injected subcutaneously into 15-day pregnant mice and by transuterine injection into foetuses of the same age. Indirect immunofluorescence was used to assess its effects on the distribution of substance P. Capsaicin administered to either the mother or the foetus crossed the placenta and depleted substance P from the primary afferent terminal field in the spinal cord and abolished reactivity in the dorsal root ganglia and peripheral terminals of spinal nerves. Subcutaneous capsaicin administration to the pregnant female is, operationally, the easiest method providing low doses are used; otherwise pregnant females seem highly susceptible to respiratory failure. These results suggest the use of capsaicin to study prenatal ontogeny of sensory nerves.
D000818:Animals; D002211:Capsaicin / Q000008:administration & dosage* / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage*; D005260:Female; D008431:Maternal-Fetal Exchange; D051379:Mice; D009475:Neurons, Afferent / Q000032:analysis / Q000502:physiology*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D013116:Spinal Cord / Q000032:analysis; D013373:Substance P / Q000032:analysis / Q000502:physiology*
D005231:Fatty Acids, Unsaturated; D013373:Substance P; D002211:Capsaicin