Pituitary adenylate cyclase-activating polypeptide promotes eccrine gland sweat secretion.

BACKGROUND: Sweat secretion is the major function of eccrine sweat glands; when this process is disturbed (paridrosis), serious skin problems can arise. To elucidate the causes of paridrosis, an improved understanding of the regulation, mechanisms and factors underlying sweat production is required. Pituitary adenylate cyclase-activating polypeptide (PACAP) exhibits pleiotropic functions that are mediated via its receptors [PACAP-specific receptor (PAC1R), vasoactive intestinal peptide (VIP) receptor type 1 (VPAC1R) and VPAC2R]. Although some studies have suggested a role for PACAP in the skin and several exocrine glands, the effects of PACAP on the process of eccrine sweat secretion have not been examined. OBJECTIVES: To investigate the effect of PACAP on eccrine sweat secretion. METHODS: Reverse transcriptase-polymerase chain reaction and immunostaining were used to determine the expression and localization of PACAP and its receptors in mouse and human eccrine sweat glands. We injected PACAP subcutaneously into the footpads of mice and used the starch-iodine test to visualize sweat-secreting glands. RESULTS: Immunostaining showed PACAP and PAC1R expression by secretory cells from mouse and human sweat glands. PACAP immunoreactivity was also localized in nerve fibres around eccrine sweat glands. PACAP significantly promoted sweat secretion at the injection site, and this could be blocked by the PAC1R-antagonist PACAP6-38. VIP, an agonist of VPAC1R and VPAC2R, failed to induce sweat secretion. CONCLUSIONS: This is the first report demonstrating that PACAP may play a crucial role in sweat secretion via its action on PAC1R located in eccrine sweat glands. The mechanisms underlying the role of PACAP in sweat secretion may provide new therapeutic options to combat sweating disorders.

Distribution of pituitary adenylate cyclase-activating polypeptide (PACAP) in the human testis and in testicular germ cell tumors.

Pituitary adenylate cyclase-activating peptide (PACAP) is a neuropeptide expressed in the central nervous system and peripheral organs. Previous studies revealed the role and distribution of PACAP in the rodent testis, however, its presence in the human testis and in testicular germ cell tumors is not known. We used RT-PCR and immunohistological observations to investigate whether human testicular tissue and testicular germ cell tumors contain PACAP. The mRNAs for PACAP and its receptors were detected in total RNA extracted from human testes. PACAP immunoreactivity was observed in spermatogonia and spermatids from normal testes. In contrast, diffuse PACAP immunopositivity was observed in seminoma tumor cells, while only faint immunoreactivity was observed in embryonal carcinoma cells. Our data suggest that PACAP may play a role in human spermatogenesis and in testicular germ cell tumor development.

Involvement of interleukin-1 in lipopolysaccaride-induced microglial activation and learning and memory deficits.

We have developed an animal model of learning and memory impairment associated with activation of microglia in the mouse brain. Injection of lipopolysaccharide into the CA1 region of the mouse hippocampus resulted in an increased production of inflammatory cytokines, such as interleukin-1ß. Immunostaining for interleukin-1ß revealed an increase in the signal at 6 hr after lipopolysaccharide injection. Immunopositive cells for interleukin-1ß were colocalized with those immunopositive for CD11b. When subacute lipopolysaccharide treatment (20 µg/2 µl/injection, bilaterally for 5 consecutive days) was performed, long-term activation of microglia and learning and memory deficits as evaluated using a step-through passive avoidance test were observed in the wild-type mice. Gene expression of the N-methyl-D-aspartate receptor NR1 and NR2A subunits was also decreased by the lipopolysaccharide treatment. In contrast, activation of microglia and the associated behavioral deficits were not observed in mice lacking interleukin-1α and -1ß following the subacute lipopolysaccharide treatment, together with little change in the gene expression of NR1 and NR2A subunits. However, the subacute lipopolysaccharide treatment produced almost similar changes in those parameters in the tumor necrosis factor-α knockout mice as in the wild-type animals. The injection of interleukin-1ß neutralizing antibody with lipopolysaccharide for 5 consecutive days resulted in the improvement of lipopolysaccharide-induced learning and memory deficits. These findings suggest that the expression of interleukin-1 plays an important role in lipopolysaccharide-induced activation of microglia and the associated functional deficits in learning and memory.

Controlled normothermia during ischemia is important for the induction of neuronal cell death after global ischemia in mouse.

A stable model of neuronal damage after ischemia is needed in mice to enable progression of transgenic strategies. We performed transient global ischemia induced by common carotid artery occlusions with and without maintaining normal rectal temperature (Trec) in order to determine the importance of body temperature control during ischemia. We measured brain temperature (Tb) during ischemia/reperfusion. Mice with normothermia (Trec within +/- 1 degrees C) had increased mortality and neuronal cell death in the CA1 region of hippocampus, which did not occur in hypothermic animals. If the Trec was kept within +/- 1 degrees C, the Tb decreased during ischemia. After reperfusion, Tb in the normothermia group developed hyperthermia, which reached > 40 degrees C and was > 2 degrees C higher than Trec. We suggest that tightly controlled normothermia and prevention of hypothermia (Trec) during ischemia are important factors in the development of a stable neuronal damage model in mice.

Regulation by orexin of feeding behaviour and locomotor activity in the goldfish.

Orexin is a hypothalamic neuropeptide that is implicated in the regulation of feeding behaviour and the sleep-wakefulness cycle in mammals. However, in spite of a growing body of knowledge concerning orexin in mammals, the orexin system and its function have not been well studied in lower vertebrates. In the present study, we first examined the effect of feeding status on the orexin-like immunoreactivity (orexin-LI) and the expression of orexin mRNA in the goldfish brain. The number of cells showing orexin-LI in the hypothalamus of goldfish brain showed a significant increase in fasted fish and a significant decrease in glucose-injected fish. The expression level of orexin mRNA in the brains of fasted fish increased compared to that of fed fish. We also examined the effect of an i.c.v. injection of orexin or an anti-orexin serum on food intake and locomotor activity in the goldfish. Administration of orexin by i.c.v. injection induced a significant increase of food intake and locomotor activity, whereas i.p. injection of glucose or i.c.v. injection of anti-orexin serum decreased food consumption. These results indicate that the orexin functions as an orexigenic factor in the goldfish brain.

Expression of tumor necrosis factor alpha (TNFalpha) following transient cerebral ischemia.

It has been considered that tumor necrosis factor alpha (TNFalpha) is participated in the Alzheimer's, and Parkinson's diseases, brain injury and brain ischemia. However, expression of TNFalpha after brain ischemia has not been demonstrated in detail. Therefore we examined the cellular expression of TNFalpha during and after transient middle cerebral artery occlusion (tMCAO) in mice by use of reverse transcriptase-polymerase chain reaction and immunohistochemical technique. TNFalpha mRNA expression was gradually increased in the neocortex of the ipsilateral hemisphere during ischemia and peaked at 1 hour after reperfusion. Then, the mRNA expression decreased and peaked again at 24 hours after reperfusion. TNFalpha-like immunoreactivities were observed in the process such as dendrite of neuron slightly before ischemia, and markedly increased in neurons in addition to the process of the ipsilateral hemisphere at 1 and 24 hours after ischemia. The results suggest that the expression of TNFalpha is up-regulated in the neurons after tMCAO. TNFalpha may induce ischemic neuronal cell death during ischemic insult.

Evaluation of neuronal cell death after a new global ischemia model in infant mice.

For the first time we set up a new model for global ischemia in the infant mice, and time-dependent changes of the blood-brain barrier (BBB) disruption and neuronal cell death were investigated in detail. Infant C57/B16 mice (postnatal 13 days) were anesthetized with inhalation of sevoflurane in N2O/O2 (70/30%) and were subjected to global ischemia by bilateral common carotid artery occlusion (CCAO) for 25 minutes. Disruption of BBB was noted at 4 hours and increased up to 24 hours after the injection of 2% Evan's Blue in the transient CCAO (tCCAO) model. Evaluation of neuronal cell death was determined with toluidine blue staining. Morphological changes of neurons after tCCAO were clearly observed in the hippocampal CA1 region but were slightly detected in the CA3 region. However, there were no morphological changes in the hippocampal dentate gyrus, the neocortex, the striatum and the hypothalamus. The number of survival neurons in the CA1 was significantly decreased at 2 days and sustained up to 4 days after tCCAO. These data indicate that this method is very useful to induce selective vulnerability in mouse hippocampus, and it provides a reliable ischemic model in infant mice.

Suppression of oxidative stress after transient focal ischemia in interleukin-1 knock out mice.

Interleukin-1 (IL-1) contributes to ischemic neurodegeneration. However, the mechanisms regulating action of IL-1 are still poorly understood. In order to clarify this central issue, mice that were gene deficient both IL-1alpha and beta (IL-1 KO) and wild-type mice were subjected to 1 hour transient middle cerebral artery occlusion (tMCAO). The concentration of 8-hydroxy deoxyguanosine (8OHdG) which is considered to be a reliable oxidative DNA damage by superoxide anion, in brain and of total nitric oxide (NO) in plasma were determined by use of HPLC. Twenty-four hours after tMCAO, the ratio of 8OHdG to dG in the ipsilateral hemisphere of wild-type mice were 2.24 x 10(-3) and 4.41 x 10(-3) in the neocortex and striatum, respectively. The concentration of 8OHdG in the ipsilateral hemisphere of the wild-type mice was higher than that of the IL-1 KO mice. The concentration of total NO in the plasma of IL-1 KO mice was also lower than that of the wild-type 24 hours after tMCAO. These results strongly suggest that IL-1 is participated in generating reactive oxygen spices and it aggravates and induces the ischemic neuronal cell death.(183 words).

[Changes in the fractal component of spectral analysis of heart rate variability and systolic blood pressure variability during the head-up tilt test].

Blood pressure and heart rate change are related to the level of physical activity, and are correlated with each other. Heart rate and blood pressure signals were investigated by coarse graining spectral analysis and changes in the harmonic and non-harmonic (fractal) power were examined during the head-up tilt test. Fourteen healthy subjects, 9 men and 5 women (mean age 30.4 +/- 1.0 years) completed the test protocol of 15 min supine rest followed by the head-up tilt (80 degrees) test. Heart rate was measured continuously with standard bipolar leads and electrocardiography. A finger cuff was placed on the left index finger for beat-by-beat recording of systolic blood pressure based on the continuous noninvasive method, and the impulse train was stored on a personal computer for spectral analysis. The harmonic component, the integrated powers in the low-frequency and high-frequency regions, and the fractal component were then calculated. The fractal component was plotted on a log power versus log frequency plane with spectral index beta estimated as the slope of the linear regression of this 1/f beta plot. RR-interval was significantly shorter during the head-up tilt position than in the supine rest position with a marked reduction in the high-frequency power. The ratio of fractal component for total power was increased and the slope beta of the 1/f beta relationship was significantly greater in the head-up tilt (1.61 +/- 0.05) than in the supine rest (0.92 +/- 0.07) position. Systolic blood pressure showed a significant increase during head-up tilt, and marked increases in high-frequency power and fractal power. However, both the ratio of fractal component for total power and the slope beta remained unchanged. Further studies are needed to clarify whether the slope beta is essentially stable or variable in some conditions.

[Evaluation of the FREEDOM O2, DC Concentrator, a portable oxygen concentrator capable of operating under car battery power].

UNLABELLED: The FREEDOM O2 DC Concentrator, an oxygen concentrator which can be powered by a car battery, was evaluated. The oxygen concentrator was used by a 67 year-old man with sequelae of pulmonary tuberculosis who was receiving long-term oxygen therapy at home (HOT), and whose work required automobile trips over long distances. The equipment used was an adsorption-type oxygen concentrator capable of operating on a DC 12 V power supply, and which can be powered from a residential power outlet (AC 100 V) using a dedicated voltage converter. The trunk-shaped equipment measured 21/584 x 42 cm and weighed 17 kg. The noise level of the equipment was 58.2 +/- 2.5 dB (at 1 meter), and the flow rate can be set to 0.25, 0.50, 0.75, 1.0, 1.5, and 2.0 l/min. RESULTS: 1) The O2 concentration which can be generated by this equipment is 93 +/- 3% (0.25 to 1.5 l/min) or 90 +/- 2.8% (2.0 l/min). 2) Using this equipment, the patient was capable of driving himself in comfort for two hours or longer. Further, it was possible to stay in a hotel during a trip, inhaling oxygen generated by the equipment. Hereafter, this equipment should enable or facilitate long-distance driving, travel and lodging for HOT patients.