Haruki Hayashi

Trigeminal nerve: the possible origin of substance p-nergic response in isolated rabbit iris sphincter muscle.

We determined the effects of trigeminal nerve denervation on the noncholinergic, nonadrenergic response to electrical transmural stimulation of the isolated rabbit iris sphincter muscle. The left ophthalmic nerve (first branch of the trigeminal nerve) was cut at the intracranial, peripheral site of the trigeminal ganglion and five to ten days later, the iris sphincter muscle isolated from the left eye (operated side) was found to produce a fast cholinergic contraction in response to electrical transmural stimulation and there was no evidence of noncholinergic, nonadrenergic contractions. On the other hand, in the iris sphincter muscle isolated from the right eye (control side), electrical transmural stimulation produced both cholinergic and noncholinergic, nonadrenergic contractile responses. Capsaicin and bradykinin produced noncholinergic, nonadrenergic contractile responses in the muscle from the control side, while in the iris sphincter from the trigeminally denervated eye there was no such response to application of these drugs. Exogenous substance P (SP) and carbachol produced a strong contractile response in both the trigeminally innervated and denervated sphincter muscles. Somatostatin, vasoactive intestinal polypeptide (VIP) and enkephalin were without effects. These observations suggest that the noncholinergic, nonadrenergic responses to electrical transmural stimulation are derived from the trigeminal nerve and that the mediator involved is probably SP or a related peptide.

Immunohistochemical studies on enteric substance P of extrinsic origin in the cat

The origin of substance P (SP)-like immunoreactivity in the Auerbachs plexuses of the esophagus, stomach duodenum was examined in the cat. The intensity of the fluorescence and the area of distribution of SP-like immunoreactivity in the Auerbachs plexuses of the cardiac part of the esophagus and the corpus of the stomach were markedly reduced by bilateral ligation of the abdominal vagus nerve, while little change occurred in the antrum of the stomach and the duodenum. After splanchnic nerve ligation or celiac ganglionectomy, the SP-like immunoreactivity in the Auerbachs plexuses of the antrum of the stomach and the duodenum was markedly reduced, whereas that in the esophagus and the corpus of the stomach was only slightly attenuated. Intense SP-like immunoreactivity was observed in the portions of the abdominal vagus and splanchnic nerve cranial to the ligation. This the Auerbachs plexuses of the esophagus, stomach and duodenum were considered to contain SP transported through the vagus and splanchnic nerve. It was also indicated experimentally that the SP-like immunoreactive fibers in the auerbachs plexus arose from the nodose and spinal ganglia as well as from the dorsal vagus nucleus in the medulla oblongata.

Effect of spinal ganglionectomy on substance P-like immunoreactivity in the gastroduodenal tract of cats

Bilateral ligation of the splanchnic nerves and spinal ganglionectomy from T5 to L2 both produced a profound decrease of substance P (SP)-like immunoreactivity in Auerbachs plexuses of the duodenum and the antrum of the stomach in the cats. As unilateral dorsal rhizotomy from T5 to L2 produced no such changes, SP is probably synthesized in the spinal ganglion and transported through the splanchnic nerve to the gastroduodenal wall.

Calcium-dependent regulation of phospholipid methylation in rabbit platelets

Effects of Ca2+ on phospholipid methylation in rabbit platelet membranes were studied using S-adenosyl-L-[3H-methyl]methionine as a substrate. The methylation was inhibited to 30% of the basal activity with 100 microM Ca2+. The inhibition was completely counteracted by various calmodulin antagonists. Their concentrations, i.e., N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide, chlorpromazine and trifluoperazine, to be required for half maximal recovery were 32, 47 and 29 microM, respectively. In contrast, N-(6-aminohexyl)-1-naphthalenesulfonamide, a weaker calmodulin antagonist, did not lead to a sufficient recovery of the inhibition. Addition of exogenous phosphatidyl-N-monomethylethanolamine (PMME) and phosphatidyl-N,N-dimethylethanolamine, intermediates of phosphatidylcholine synthesis by successive methylation of phosphatidylethanolamine (PE), enhanced the formation of 3H-methylated products. However, the increased amount of 3H-methylated products by the addition of those intermediates was much the same either in the presence or absence of Ca2+. These results suggest that the Ca2+-induced inhibition of methylation in platelets is mediated either by calmodulin itself or by a site which has calmodulin antagonist binding properties similar to this protein and that Ca2+ seems to inhibit the first step of the methylation to form PMME from PE.

Expression of CD45-Restricted Form B in (NZW × BXSB) F1 and MRL/Mp-1pr/1pr Mice

Expression of CD45RB on CD4+ or CD8+ cells in combination with TCRV beta usages (V beta 6, V beta 8.1, V beta 8.2, V beta 11 and V beta 17a) in normal mouse strains (BALD/c and C57BL/6) was compared with autoimmune-prone strains (NZW x BXSB) F1 and MRL/lpr) at young and old ages. The frequencies, and also the numbers of CD45RB- cells in CD4+ T cells with various TcR repertoires was significantly less in the autoimmune-prone stains at old ages, while, in normal control strains, they remained unchanged. Furthermore, CD4+/CD45RB- cells are CD44high and CD62L (L- selectin).low These findings suggest that most T cells, especially CD4+ T cells, in old W/BF1 and old MRL/lpr mice, were activated and this may reflect the elevation of autoantibodies and the progress of autoimmune status in aged autoimmune-prone mice. This will be discussed in relation to the progress of the autoimmune diseases.

Do the substance P-ergic vagus afferents in cats reinnervate the deafferented superior cervical ganglion?

By ligating specific nerves in the cat, the central processes of the nodose ganglion (NG) cells containing substance P-like immunoreactive materials were shown, immunohistochemically, to run through the cross-anastomosis made between the cranial end of the NG and the caudal end of the superior cervical ganglion (SCG), and to reach the portions cranial to the SCG without making synaptic contacts with the SCG cells.