neural and non-neural localization of vip-like immunoreactivity in the skin of cat, dog and man
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Neural and Non-Neural Localization of VIP-like Immunoreactivity in the Skin of Cat, Dog and Man~ W.HARTSCHUH, E.WEIHE, M.REII~ECKE, N.YANAII{ARA (Dermatological Clinic and Inst. of Anatomy, Univ. of Heidelberg, West-Germany; Shizuoka College of Pharmacy, Japan)
There are no reports which indicate that cutaneous vasoactive intestin- al polypeptide is present in other than neural locations. The prese~ light microscopic immunohistochemical study was undertaken to determine the histotopographic distribution of VIP-immunoreactive (IR) skin nerves and of whether Merkel cells contain VIP-immunoreactivity. Bouin-fixed skin specimens of cat, dog and man from various body regions were analy- sed by using the peroxidase-antiperoxidase technique with several regi- on-specific antisera. In all species investigated and with all VIP-anti- sera used similar distribution patterns of VIP-IR nerve fibers were ob- served. VIP-IR nerves supplied all segments of skin vasculature, i.e. arteries, veins, arterioles, venules ~nd some capillaries of of sweat glands and of sebaceous glands. The papillary loop vessels only very occasionally received VIP-IR nerve supply. A very dense plexus of VIP-IR nerves was delivered to arteriovenous anastomosis. Some non-vascular nerve fibers were seen in contact with dermal smooth muscle strands, in eccrine sweat glands targeting glandular cells, around sebacceous ~lands and particularly in Meibomian glands. In addition VIP-IR nerves occured in the region of upper hair follicles. In non-neural location VIP-immu- noreactivity was seen in numerous Merkel cells of sinus hair follicles from cat and dog. After degeneration of Merkel cell axons induced by ex- hairesis of the infraorbital nerve which supples the sinus hair follic- les Merkel cells persisted to be VIP-IR. In the basal epidermis of fin- ger and toe from man VIP-IR Merkel cells were also found. The sensory Merkel cell axons were consistently not VIP-IR. It is conceivable that VIP is physiologically released from both its neural and non-neural cu- taneous pool. VIP may have an impact on thermore~ulation by influencing blood flow and sweat production and modulste herkel cell axon perceptiom
Effect of VIP on 5-HT release in the suprachiasmatlc nucleus of the rat. oestradio1. M. HERY, M. FAUDON and F. HERY (INSERM - U.6 and CNRS - GR.45, Marguerlte, 13009 Marseille, France)
Modulatlon by 280 Bd sainte-
The combined autoradlographic and immunocytochem[cal method has shown axosomatic and • 3 axodendritzc contacts between H(5-HT) labelled terminals and vasoactive intestinal peptide (VIP) neurons
in the suprachlasmatic nucleus (SCN) of the rat ( I ) . We have previously shown a stimulating effect of VIP on 5-HT release in the SCN. Oestradiol (E2) modulates 5-HT metabollsm in the SCN (2). In the present work, we test the following hypothesis : Is VIP effect on 5-HT release modified by ~ impregnation ? In order to investigate the role of E 2 in this interaction, Fragments of medio-rostrobasal hypotha]amus (including pr lncipal ly the SCN) taken from males, ovar[ectomized females (OVX) or OVX E 2 implanted female rats (OVX EZ), were superfused in a r t i f l c l a l LCR. We measured the release of 3H(5-HT) newly synthesized From L-3H-tryptophan (infused at the beginning of superfuslon during 20 mln). When the level of 3H(5-HI) release was stabi l ized, addltion of VIP (I0-7M) during 15 min leads to an increase of 5-HT release (+ 600% during 15 mln) from SCN of male or OVX in 72% of experiments. The effect of VIP on 5-HI release is inhibited par t ia l ly or completely (94% of experiments) when hypothalamlc fragments are taken from OVX E2. The Faci l i tatory effect of VIP on 5-HT release may be par t ia l ly explained by an action of pept[de on the reuptake of 5-HT. Indeed VIP decreases (40% to 50%) the uptake of 5-HT in SCN taken from males or OVX rats, whereas i t is without effect on SCN From OVX E2. These results suggest a regulation by VIP of 5-HT metabolism in the SCN and a modulation of this effect by E2. Since the peptide and serotonin have been implicated in the secretion of gonadotropin hormone (3,4), the effect observed could give am account of a regulatory system including an hormone (E2), a neuropeptlde (VIP) and a neurotransmitter (5-HT), in the control of gonadotropln function.
( i ) BOSLER 0., Doctorat d'6tat, Marseille, 1983. (2) HERY M. e t a ] . , J. Endocr. g4 (1982) 157-166. (3) HERY M. et aT., Endocr. 102 (1978) I01g-I025. (4) SAMSON W.K., Reg. Pept. 2 (1981) 253-264.