Arnold Eskin

Arnold Eskin was a professor of chronobiology at the University of Houston in Houston, Texas. He attended Vanderbilt University, where he received a degree in physics. He later attended University of Texas at Austin, where he received his Ph.D. in zoology in 1969. In it, Eskin and Menaker showed the scientific community the ability of house sparrows to entrain to auditory cues as opposed to previously shown light cues.

Role of glutamate transporters in memory formation Eskin's lab has extensively studied the role of glutamate transporters in synaptic plasticity in aplysia. Specifically, his group has shown that glutamate uptake increases during long-term sensitization in Aplysia, long-term potentiation (LTP) in the hippocampus of rats, and morphine addiction and withdrawal in rats. Deficiencies in glutamate uptake during changes in synaptic efficacy have also been linked to diseases such as Amyotrophic lateral sclerosis (ALS), Alzheimer's disease, and Epilepsy. Blockage of NMDA receptors prevents glutamate from binding, which prevents the formation of long-term memory. Eskin's group believes that the mechanism for glutamate uptake is phylogenetically conserved for multiple types of synaptic plasticity. They currently study the mechanism by which this process takes place. He and his lab have shown that an aplysia's ability to form long-term memory is dependent on the time of day, namely that aplysia are able to form long-term memories during the day, but are unable to at night. This was done via regulation of several factors, including neurotransmitter release, MAPK signaling, and immediate early gene expression. Short-term memory, however, has not been shown to vary based on time of day. The mechanism by which this occurs is not currently understood, but Eskin and his lab have continued to study the circadian characteristics of glutamate uptake in synaptic plasticity in order to learn more about the mechanism by which memory formation is controlled by a circadian clock.

Model use The Eskinogram has notably been used to model how the suprachiasmatic nucleus (SCN) acts as a master oscillator for the human biological clock. A group of photoreceptors called the intrinsically photosensitive retinal ganglion cells (ipRGCs) act as the input for the clock mechanism. These cells then use a pathway dependent on melanopsin to signal to the SCN. The SCN then uses a transcription-translation feedback loop, consisting of a set of clock genes that regulate their own expression, to act as a complete oscillator and signal locomotor outputs accordingly.

Awards and honors For his contributions to the Department of Biology and Biochemistry, Eskin received the 25th Esther Farfel Award from the University of Houston in 2003. Serving as department chair from 1994 to 2000, he established a focus on research in neuroscience, biological clocks, and infectious disease and tripled research grants to the department. In the same year, Eskin also received the John and Rebecca Moores Professors Award from the University of Houston.