Substance P, Free Acid

The effects of substance P and substance K, which are coexpressed in the same mRNA as a beta-preprotachykinin in peripheral tissues and released in the inflammatory lesion of the skin, were examined on epidermal proliferation using spontaneously transformed mouse epidermal cell line (Pam 212 cells). Substance P stimulated the synthesis of DNA of Pam 212 cells in the medium containing 2%-10% fetal calf serum (FCS). Stimulation of DNA synthesis was dose dependent if the cells were cultured in the medium containing 2% FCS (quiescent condition). This effect was inhibited by spantide. In a serum-free medium, substance P had no effect on keratinocyte proliferation. In contrast, substance K, which shares a common amino acid sequence with substance P on its C-terminal, did not affect DNA synthesis of Pam 212 cells in either medium condition. Substance P released in inflammation may stimulate epidermal proliferation.

Depression is a multicausal disorder and has been associated with the risk to develop cancer, dementia, diabetes, epilepsy and stroke. As a metabolic disorder depression has been associated with obesity, diabetes, insulin sensitivity, neuropeptide Y, glucose regulation, poor glycemic control, glucagone-like peptide-1, cholezystokinin, ghrelin, leptin, the endocannabinoid system, insulin-like growth factor and gastrin-releasing peptide. As a cardiovascular disease a close relationship exists between depression and blood pressure, heart rate, norepinephrine, sympathetic tone, vascular resistance, blood viscosity, plasma volume, intima thickness and atherosclerosis. Additionally blood coagulation, fibrinolysis, D-dimers, plasminogen activator inhibitor-1 protein, platelet activation, VEGF, plasma nitric oxide and its synthase are changed in depressed patients. As an endocrinological and stress disorder depression has been connected with the concentration of free T4, TSH, CRH, arginine vasopressin, corticotrophin, corticosteroid release and ACTH. Depression as an inflammatory disorder is mediated by pro-inflammatory cytokines, interleukin-1, interleukin-6, TNF-alpha, soluble interleukin-2 receptors, interferon-alpha, interleukin 8, interleukin-10, hs-CRP, acute phase proteins, haptoglobin, toll like receptor 4, interleukin-1beta, mammalian target of rapamycin pathway, substance P, cyclooxygenase-2, prostaglandin-E2, lipid peroxidation levels and acid sphingomyelinase. Nutritional factors might influence depression risk, i.e. the consumption of folate, omega-3 fatty acids, monounsaturated fatty acids, olive oil, fish, fruits, vegetables, nuts, legumes, vitamin B6 and vitamin B12. The neurodegenerative hypothesis of depression explains decreased hippocampal volumes in depressed patients and changes of neurotrophic support by BDNF, erythropoietin, GDNF, FGF-2, NT3, NGF and growth hormone. In this context, a fast neuroprotective and antidepressant effect has also been observed by ketamine, which acts via the glutamatergic system. Hence, GABA, AMPA, EAAT, NMDA- and metabotropic glutamate receptors (mGluR1 to mGluR8) have gained interest in depression recently. Alternative, causative or also easy available treatment strategies beyond serotonin and noradrenaline reuptake inhibition might be a major topic of future psychiatric care. In this review, an attempt is made to overview concepts of the disease and search for perspectives on antidepressant treatment strategies beyond approved medications.

Substance P, 5-hydroxytryptamine, and gamma-aminobutyric acid levels in saliva were measured in 55 patients with migraine during headache attacks (15 men and 40 women, average age 37.6 years), 36 patients with migraine in interictal periods (8 men and 28 women, average age 43.9 years), 48 patients with tension-type headache during headache attacks (18 men and 30 women, average age 47.3 years), and 25 patients with tension-type headache in interictal periods (10 men and 15 women, average age 48.6 years). Forty-three normal healthy volunteers composed the control group (17 men and 26 women, average age 32.7 years). Substance P levels in saliva were determined using competitive enzyme-linked immunosorbent assay, and were 26.9 +/- 45.1 pmol/mL in the patients with migraine during headache attacks, 30.0 +/- 59.7 pmol/mL in the patients with migraine in interictal periods, 243.5 +/- 1137 pmol/mL in the patients with tension-type headache during headache attacks, 101.3 +/- 364 pmol/mL in the patients with tension-type headache in interictal periods, and 21.2 +/- 17.4 pmol/mL in the healthy controls. 5-hydroxytryptamine levels in saliva were determined using reversed-phase high-performance liquid chromatography with electrochemical detection, and were 895 +/- 1075 ng/mL in the patients with migraine during headache attacks, 758 +/- 1375 ng/mL in the patients with migraine in interictal periods, 1646 +/- 1945 ng/mL in the patients with tension-type headache during active headache periods, 1167 +/- 1495 ng/mL in the patients with tension-type in headache-free periods, and 450 +/- 405 ng/mL in the healthy controls. Gamma-aminobutyric acid levels in saliva were determined using high-performance liquid chromatography with precolumn ortho-phthalaldehyde fluorescence detection. Gamma-aminobutyric acid levels in saliva were 36.8 +/- 49.8 pmol/mL in the patients with migraine during headache attacks, 17.9 +/- 25.2 pmol/mL in the patients with migraine in interictal periods, 16.0 +/- 18.3 pmol/mL in the patients with tension-type headache during active headache periods, 14.1 +/- 6.8 pmol/mL in the patients with tension-type headache in headache-free periods, and 21.6 +/- 22.7 pmol/mL in the healthy controls. The salivary substance P and 5-hydroxytryptamine levels in the patients with tension-type headache during active headache periods were significantly higher than those in healthy controls. In contrast, we found no significant differences between the salivary gamma-aminobutyric acid levels in the patients with tension-type headache and healthy controls. The high levels of salivary substance P and 5-hydroxytryptamine in tension-type headache patients during headache periods might reflect release of substance P from the pain sensory system. Saliva could represent a fluid particularly suitable to the study of neuropeptide release under specific conditions such as migraine and tension-type headache.