Martin H Smith

Prevention of plasticity of endocannabinoid signaling inhibits persistent limbic hyperexcitability caused by developmental seizures.

Depolarization-induced suppression of inhibition (DSI) is an endocannabinoid-mediated short-term plasticity mechanism that couples postsynaptic Ca2+ rises to decreased presynaptic GABA release. Whether the gain of this retrograde synaptic mechanism is subject to long-term modulation by glutamatergic excitatory inputs is not known. Here, we demonstrate that activity-dependent long-term DSI potentiation takes place in hippocampal slices after tetanic stimulation of Schaffer collateral synapses. This activity-dependent, long-term plasticity of endocannabinoid signaling was specific to GABAergic synapses, as it occurred without increases in the depolarization-induced suppression of excitation. Induction of tetanus-induced DSI potentiation in vitro required a complex pathway involving AMPA/kainate and metabotropic glutamate receptor as well as CB1 receptor activation. Because DSI potentiation has been suggested to play a role in persistent limbic hyperexcitability after prolonged seizures in the developing brain, we used these mechanistic insights into activity-dependent DSI potentiation to test whether interference with the induction of DSI potentiation prevents seizure-induced long-term hyperexcitability. The results showed that the in vitro, tetanus-induced DSI potentiation was occluded by previous in vivo fever-induced (febrile) seizures, indicating a common pathway. Accordingly, application of CB1 receptor antagonists during febrile seizures in vivo blocked the seizure-induced persistent DSI potentiation, abolished the seizure-induced upregulation of CB1 receptors, and prevented the emergence of long-term limbic hyperexcitability. These results reveal a new form of activity-dependent, long-term plasticity of endocannabinoid signaling at perisomatic GABAergic synapses, and demonstrate that blocking the induction of this plasticity abolishes the long-term effects of prolonged febrile seizures in the developing brain.

Swine - From the Animal's Point of View, 4: Pig Disease

Author(s): Smith, Martin H; Meehan, Cheryl L; Ma, Justine M; Hisakawa, Nao; Dasher, H Steve; Camarillo, Joe D | Abstract: Part 4 of the Swine - From the Animals Point of View Series, a 4-H Youth Development curriculum that introduces youth to many aspects of pig care.

Swine - From the Animal's Point of View, 2: Pig Housing

Author(s): Smith, Martin H; Meehan, Cheryl L; Ma, Justine M; Hisakawa, Nao; Dasher, H Steve; Camarillo, Joe D | Abstract: Part 2 of the Swine - From the Animals Point of View Series, a 4-H Youth Development curriculum that introduces youth to many aspects of pig care.

Sheep - From the Animal's Point of View, 5: Sheep Care and Responsibility

Author(s): Smith, Martin H.; Meehan, Cheryl L.; Ma, Justine M.; Hisakawa, Nao; Dasher, H. Steve; Camarillo, Joe D. | Abstract: Part 5 of the Sheep - From the Animals Point of View Series, a 4-H Youth Development curriculum that introduces youth to many aspects of sheep care.

Youth Development through Veterinary Science, 11: Is Your Snake Sick?

Author(s): Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Spitze, Naomi | Abstract: Part 11 of the Youth Development through Veterinary Science Series, a 4H Youth Development curriculum that introduces youth to many aspects of veterinary science.

Youth Development through Veterinary Science, 9: Is Your Goat Feeling Green

Author(s): Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Moses, Adele; Wong, Joyce | Abstract: Part 9 of the Youth Development through Veterinary Science Series, a 4H Youth Development curriculum that introduces youth to many aspects of veterinary science.

Youth Development through Veterinary Science, 8: Is Your Dog Feeling Down?

Author(s): Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Moses, Adele; Wong, Joyce | Abstract: Part 8 of the Youth Development through Veterinary Science Series, a 4H Youth Development curriculum that introduces youth to many aspects of veterinary science.

Youth Development through Veterinary Science Complete (Parts 1 through 11)

Author(s): Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Lau, Tiffany; Liang, Justin; Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Allaband, Celeste; Alupay, Jean; Techanun, Jennifer; Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Lau, Tiffany; Liang, Justin; Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Pracht-Smith, Eleanor I; Eng, Carlin; Hauert, Rebekka; Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Liang, Justin; Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Simoes, Kelly Lister; Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Allaband, Celeste; Alupay, Jean; Techanun, Jennifer; Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Moses, Adele; Wong, Joyce; Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Moses, Adele; Wong, Joyce; Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Hauert, Rebekka; Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Spitze, Naomi | Abstract: The Youth Development through Veterinary Science Series is a 4H Youth Development curriculum that introduces youth to many aspects of veterinary science. This download includes the entire series, parts 1 through 11.

Youth Development through Veterinary Science, 10: Is Your Horse Healthy?

Author(s): Smith, Martin H; Meehan, Cheryl L; Ma, Justine; Dasher, H Steve; Camarillo, Joe D; Hauert, Rebekka | Abstract: Part 10 of the Youth Development through Veterinary Science Series, a 4H Youth Development curriculum that introduces youth to many aspects of veterinary science.