AB5398 Sigma-AldrichAnti-Vanilloid Receptor Like Protein 1 Antibody, pain, CT

The myocardial response to exercise is an adaptive mechanism that permits the heart to maintain cardiac output via improved cardiac function and development of hypertrophy. There are many overlapping mechanisms via which this occurs with calcium handling being a crucial component of this process. Our laboratory has previously found that the stretch sensitive TRPV2 channels are active regulators of calcium handling and cardiac function under baseline conditions based on our observations that TRPV2-KO mice have impaired cardiac function at baseline. The focus of this study was to determine the cardiac function of TRPV2-KO mice under exercise conditions. We measured skeletal muscle at baseline in WT and TRPV2-KO mice and subjected them to various exercise protocols and measured the cardiac response using echocardiography and molecular markers. Our results demonstrate that the TRPV2-KO mouse did not tolerate forced exercise although they became increasingly exercise tolerant with voluntary exercise. This occurs as the cardiac function deteriorates further with exercise. Thus, our conclusion is that TRPV2-KO mice have impaired cardiac functional response to exercise.

The heart has a dynamic compensatory mechanism for haemodynamic stress. However, the molecular details of how mechanical forces are transduced in the heart are unclear. Here we show that the transient receptor potential, vanilloid family type 2 (TRPV2) cation channel is critical for the maintenance of cardiac structure and function. Within 4 days of eliminating TRPV2 from hearts of the adult mice, cardiac function declines severely, with disorganization of the intercalated discs that support mechanical coupling with neighbouring myocytes and myocardial conduction defects. After 9 days, cell shortening and Ca(2+) handling by single myocytes are impaired in TRPV2-deficient hearts. TRPV2-deficient neonatal cardiomyocytes form no intercalated discs and show no extracellular Ca(2+)-dependent intracellular Ca(2+) increase and insulin-like growth factor (IGF-1) secretion in response to stretch stimulation. We further demonstrate that IGF-1 receptor/PI3K/Akt pathway signalling is significantly downregulated in TRPV2-deficient hearts, and that IGF-1 administration partially prevents chamber dilation and impairment in cardiac pump function in these hearts. Our results improve our understanding of the molecular processes underlying the maintenance of cardiac structure and function.

A recent study has demonstrated that increasing the intrathoracic temperature from 36 degrees C to 41 degrees C induced a distinct stimulatory and sensitizing effect on vagal pulmonary C-fiber afferents in anesthetized rats (J Physiol 565: 295-308, 2005). We postulated that these responses are mediated through a direct activation of the temperature-sensitive transient receptor potential vanilloid (TRPV) receptors by hyperthermia. To test this hypothesis, we studied the effect of increasing temperature on pulmonary sensory neurons that were isolated from adult rat nodose/jugular ganglion and identified by retrograde labeling, using the whole cell perforated patch-clamping technique. Our results showed that increasing temperature from 23 degrees C (or 35 degrees C) to 41 degrees C in a ramp pattern evoked an inward current, which began to emerge after exceeding a threshold of approximately 34.4 degrees C and then increased sharply in amplitude as the temperature was further increased, reaching a peak current of 173 +/- 27 pA (n = 75) at 41 degrees C. The temperature coefficient, Q10, was 29.5 +/- 6.4 over the range of 35-41 degrees C. The peak inward current was only partially blocked by pretreatment with capsazepine (Delta I = 48.1 +/- 4.7%, n = 11) or AMG 9810 (Delta I = 59.2 +/- 7.8%, n = 8), selective antagonists of the TRPV1 channel, but almost completely abolished (Delta I = 96.3 +/- 2.3%) by ruthenium red, an effective blocker of TRPV1-4 channels. Furthermore, positive expressions of TRPV1-4 transcripts and proteins in these neurons were demonstrated by RT-PCR and immunohistochemistry experiments, respectively. On the basis of these results, we conclude that increasing temperature within the normal physiological range can exert a direct stimulatory effect on pulmonary sensory neurons, and this effect is mediated through the activation of TRPV1, as well as other subtypes of TRPV channels.

PURPOSE: Analogous to interstitial cells of Cajal in the bowel, functional important networks of interstitial cells could have a role in the complex mechanism of central and peripheral control of urinary tract function. Recently various reports mentioned the presence of interstitial cells in different parts of the urinary tract and in different species. Since important differences among species exist, we performed immunohistochemistry on fresh frozen human tissue to study the presence of interstitial cells in the human urinary tract. MATERIALS AND METHODS: A total of 65 tissue pieces from all levels of the urinary tract were obtained from 44 patients treated at our institution. Tissue was processed for immunohistochemistry immediately after removal. We performed immunohistochemistry for kit, connexin 43 and VRL1/TRPV2. RESULTS: Interstitial cells immunopositive for all 3 antibodies were seen beneath the urothelium and between smooth muscle cells in all tissue pieces with slight topographical differences. CONCLUSIONS: Together with morphological and functional data from other experiments these morphological data suggest that, as in the bowel, networks of interstitial cells might have an important role in the physiology and pathology of the urinary tract. They could be involved in pacemaking or have an integrating role through the modulation of neurotransmission and conduction of electrical impulses. Functional experiments are the next step to study these hypotheses.

PURPOSE: We determined the presence and distribution of vanilloid receptor-1 in the human bladder and confirmed or rejected previous findings of other groups that used indirect methods or vanilloid receptor-1 antibodies made by immunizing experimental animals. Also, we tested the reproducibility of results using commercially available antibodies against the N-terminus and C-terminus of the vanilloid receptor. MATERIALS AND METHODS: A total of 11 normal bladder tissue samples were obtained from cystectomy specimens and fresh frozen processed. Specimens were studied by immunohistochemistry and confocal laser microscopy using 3 vanilloid receptor-1 antibodies. Immunohistochemical co-localization studies for neurofilament, neuronal nitric oxide synthase and nerve growth factor were performed. RESULTS: Our results confirm the presence of vanilloid receptor-1 on nonmyelinated and myelinated nerve fibers. There was vanilloid receptor-1 immunoreactivity on smooth muscle cells but different sensitivities for the antibodies. There was immunoreactivity on interstitial cells located in the suburothelium and intermuscular septa of the muscularis. There was co-localization of neuronal nitric oxide synthase with interstitial cells but not with neurofilament. No co-localization was found for nerve growth factor and vanilloid receptor-1. CONCLUSIONS: Vanilloid receptor-1 is located on small unmyelinated and myelinated nerve fibers. In addition, vanilloid receptor-1 is also present on interstitial cells in the suburothelium. There is smooth muscle cell immunoreactivity but a difference in antibodies raised against the C-terminus and N-terminus. These data suggest that the current hypothesis about the mechanism of action of vanilloids is through blocking the afferent reflex arc must be revised and the function of interstitial cells deserves further attention.