Neuroscience as a discipline is rarely covered in educational institutions in Puerto Rico. In an effort to overcome this deficit we developed the Bridge to Neuroscience Workshop (BNW), a full-day hands-on workshop in neuroscience education. BNW was conceived as an auxiliary component of a parent recruitment program called Bridge to the PhD in Neuroscience Program (BPNP). The objectives of BNW are to identify promising students for BPNP, and to increase awareness of neuroscience as a discipline and a career option. BNW introduces basic concepts in neuroscience using a variety of educational techniques, including mini-lectures, interactive discussions, case studies, experimentation, and a sheep brain dissection. Since its inception in 2011 BNW has undergone a series of transformations that continue to improve upon an already successful and influential educational program for underrepresented minorities. As of Fall 2018, we have presented 21 workshops, impacting 200 high school and 424 undergraduate students. BNW has been offered at University of Puerto Rico (UPR)-Arecibo, UPR-Cayey, UPR-Humacao, Pontificia Universidad Católica de Ponce, and Universidad Interamericana de Puerto Rico-Arecibo. A pre-and post evaluation was given to evaluate material comprehension and thus measure effectiveness of our one-day interactive workshop. Our results suggest that both high school and undergraduate students have little prior knowledge of neuroscience, and that participation in BNW improves not only understanding, but also enthusiasm for the discipline. Currently, our assessment has only been able to evaluate short-term effects (e.g. comprehension and learning). Therefore, our current focus is developing methods capable of determining how participation in BNW impacts future academic and career decisions.

There is evidence that R-type Ca2+ channels contribute to synaptic transmission in the myenteric plexus. It is unknown if R-type Ca2+ channels contribute to neuromuscular transmission. We measured the effects of the nitric oxide synthase (NOS) inhibitor, nitro L-arginine (NLA), Ca2+ channel blockers and apamin (SK channel blocker) on neurogenic relaxations and contractions of the guinea pig ileum longitudinal muscle-myenteric plexus (LMMP) in vitro. We used intracellular recordings to measure inhibitory junction potentials (IJPs). Immunohistochemical and western blot techniques localized R-type Ca2+ channel protein in the LMMP and circular muscle. CdCl2 (pan Ca2+ channel blocker) blocked and NLA and NiCl2 (R-type Ca2+ channel blocker) reduced neurogenic relaxations in a non-additive manner. NiCl2 did not alter neurogenic cholinergic contractions but it potentiated neurogenic non-cholinergic contractions. Relaxations were inhibited by apamin, NiCl2 and NLA and were blocked by combined application of these drugs. Relaxations were reduced by NiCl2 or ω-conotoxin (ω-CTX, N-type Ca2+ channel blocker) and were blocked by combined application of these drugs. Longitudinal muscle IJPs were inhibited by NiCl2, but not MRS 2179 (P2Y1 receptor antagonist). Circular muscle IJPs were blocked by apamin, MRS 2179, ω-CTX and CdCl2 but not NiCl2. We conclude that neuronal R-type Ca2+ channels contribute to inhibitory neurotransmission to longitudinal muscle but less so or not all in the circular muscle of the guinea pig ileum.

BackgroundThe enteric nervous system controls gastrointestinal motility. Multiple subtypes of voltage‐gated Ca2+channels contribute to neurotransmitter release from enteric neurons.ObjectiveWe tested the hypothesis that R‐type Ca2+channels contribute to enteric neurotransmitter release in the mouse colon.MethodsStudies were done in vivo and in vitro using wild type (WT) and a1E Ca2+ channel (R‐type) knockout (KO) mice. Fecal output was measured in vivo. The colonic migrating motor complex (CMMC) was measured in vitro. We used NiCl2 (50 mM) to block R‐type Ca2+ channels , Ω‐conotoxin (CTX, 0.1 mM) to block N‐type Ca2+ channels and tetrodotoxin (TTX, Na+ channel blocker, 0.3 mM) on CMMCs.ResultsThere was no significant difference in fecal output between a1E KO and WT mice. There was no difference in the frequency, propagation speed or amplitude of CMMC contractions between colons from WT and a1E KO mice. NiCl2 slightly decreased contraction amplitude in colons from a1E KO and WT mice. CTX and TTX completely blocked neurogenic contractions and disrupted the CMMC pattern, leaving only spontaneous myogenic contractions behind.ConclusionThese results suggest that either R‐type Ca2+ channels have a minor role in controlling colonic motility, or that there is compensatory upregulation of other Ca2+ types in the constitutive a1E KO mice.*Supported by: R01DK094932

The inhibitory neurotransmitters, ATP and nitric oxide (NO), relax the colonic smooth muscle which is important for propulsion of colonic content. Voltage‐gated Ca2+ channels (VGCC) control neurotransmitter release and regulate colonic motility. The α1E subunit of the R‐type VGCC is expressed by enteric neurons yet its role in regulating colonic motility is unclear. We investigated the role of R‐type VGCCs in colonic inhibitory neuromuscular transmission using alpha1E knockout (KO) mice. Intracellular recordings of inhibitory junction potentials (IJP) were obtained from circular muscle cells in distal colon. IJPs were evoked by trains of electrical stimulation (1s, 10 Hz, 40‐90 volts). IJPs have a fast ATP‐mediated component and a slow NO‐mediated component. Peak amplitude (ATP component) and area under the curve (AUC; both components) of the IJP were compared between wildtype (WT) and KO mice. Resting membrane potential (RMP) was measured as an index of ongoing inhibitory transmission. There was a voltage dependent increase in IJP amplitude and AUC in WT and KO mice. IJP amplitude was similar in WT and KO mice. The IJP AUC was decreased in KO compared to WT. Nifedipine (1 µM; L‐type VGCC blocker) had no effect on these responses. RMP in KO muscle cells was decreased compared with WT (‐44 ± 2 mV in WT and ‐38 ± 1 mV in KO; P < 0.05). Thus, there was a 5.4 mV RMP depolarization in KO mice. Nifedipine did not change RMP of WT or KO cells (‐39 ± 3 mV, WT and ‐40 ± 1 mV in KO). In conclusion, R‐type VGCCs contribute to colonic inhibitory neuromuscular transmission by controlling NO release. In addition, R‐type VGCCs contribute to ongoing release of NO and ATP which maintain colonic muscle tone.