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Papers by Michelle Mundorf
Synapse, Apr 9, 2002
The release and clearance of electrically evoked catecholamine (CA) in the ventral portion of the... more The release and clearance of electrically evoked catecholamine (CA) in the ventral portion of the bed nucleus of the stria terminalis (BSTV) in mouse brain slices was evaluated with fast‐scan cyclic voltammetry at carbon‐fiber microelectrodes (CFME). Uptake in this region was observed to be markedly slower than in the caudate putamen (CPu). Clearance rates were reduced in the BSTV in both norepinephrine transporter knockout (NET KO) and dopamine transporter knockout (DAT KO) mice when compared to results in wild‐type (WT) mice. However, uptake was faster in the BSTV in both the DAT and NET KO mice than in the CPu of DAT KO mice. This indicates that both transporters play a role in CA clearance in the BSTV. The transporters restrict extracellular CA to the general area of the BSTV, as revealed by the diminished signal as the CFME is moved sequentially further and further from the site where CA release is evoked. However, in slices from the DAT KOs and NET KOs, CA release could be observed outside of the BSTV region during such experiments. These results show that the low rate uptake in the BSTV facilitates extrasynaptic diffusion of catecholamine, but that uptake still regulates and limits the range of the transmitter to the region. Slower clearance from the extracellular fluid allows the released CA to act as a volume transmitter and diffuse to distant sites within the region to exert its neurochemical action. Synapse 44:188–197, 2002. © 2002 Wiley‐Liss, Inc.
Clinical and Experimental Optometry, May 1, 2016
Current protocols in neuroscience, Feb 1, 2002
Amperometry and cyclic voltammetry are two electrochemical techniques that enable the detection o... more Amperometry and cyclic voltammetry are two electrochemical techniques that enable the detection of electroactive neurotransmitters that are released from single cells. These techniques have provided the first chemical view of the events that occur during exocytosis. This unit describes the isolation of several cell types known for their exocytotic properties, the fabrication and calibration of carbon fiber microelectrodes, as well as some of the equipment and software requirements for obtaining electrochemically generated data.
Annals of the New York Academy of Sciences, Oct 1, 2002
Contact Lens and Anterior Eye, Apr 1, 2016
Contact Lens and Anterior Eye, Jun 1, 2018
Annals of the New York Academy of Sciences, Oct 1, 2002
Carolina Digital Repository (University of North Carolina at Chapel Hill), 2000
Eye & Contact Lens-science and Clinical Practice, Nov 1, 2018
Objectives: Cosmetic contact lenses are increasingly popular because of their eye enhancing cosme... more Objectives: Cosmetic contact lenses are increasingly popular because of their eye enhancing cosmetic benefits. The pigment particles used in these lenses can impact lens surface characteristics. This article examines the surface characteristics and the differences between the clear and the pigmented regions among five limbal ring design lenses. Methods: Scanning electron microscopy was used to determine the location and depth of the pigment particles from the lens surface. The coefficient of friction (CoF) was determined with a Basalt-MUST microtribometer at clear and pigmented regions on either the front or the back surface. Atomic force microscopy was used to determine the surface roughness of each lens in root-mean-square (RMS) units at clear and pigmented regions. A linear mixed model for repeated measures was used for the analysis of the CoF and RMS roughness to compare all lenses. Results: Four lens types had pigments exposed on the surface and one lens type had pigment fully enclosed. The CoF difference between clear and pigmented regions were similar and not statistically significant (P¼0.0124) for the lens type with pigments enclosed, whereas the CoF difference for the other four lens types showed statistically significant difference (P,0.0001). Conclusions: Of the lenses tested here, cosmetic contact lenses with pigments enclosed in the lens matrix provided a more consistent surface between clear and pigmented regions compared with lenses that had exposed pigments.
Investigative Ophthalmology & Visual Science, 2020
Contact Lens and Anterior Eye, 2018
Eye & Contact Lens: Science & Clinical Practice, 2018
Objectives: Cosmetic contact lenses are increasingly popular because of their eye enhancing cosme... more Objectives: Cosmetic contact lenses are increasingly popular because of their eye enhancing cosmetic benefits. The pigment particles used in these lenses can impact lens surface characteristics. This article examines the surface characteristics and the differences between the clear and the pigmented regions among five limbal ring design lenses. Methods: Scanning electron microscopy was used to determine the location and depth of the pigment particles from the lens surface. The coefficient of friction (CoF) was determined with a Basalt-MUST microtribometer at clear and pigmented regions on either the front or the back surface. Atomic force microscopy was used to determine the surface roughness of each lens in root-mean-square (RMS) units at clear and pigmented regions. A linear mixed model for repeated measures was used for the analysis of the CoF and RMS roughness to compare all lenses. Results: Four lens types had pigments exposed on the surface and one lens type had pigment fully enclosed. The CoF difference between clear and pigmented regions were similar and not statistically significant (P¼0.0124) for the lens type with pigments enclosed, whereas the CoF difference for the other four lens types showed statistically significant difference (P,0.0001). Conclusions: Of the lenses tested here, cosmetic contact lenses with pigments enclosed in the lens matrix provided a more consistent surface between clear and pigmented regions compared with lenses that had exposed pigments.
Clinical and Experimental Optometry, 2016
Contact Lens and Anterior Eye, 2016
Current Protocols in Neuroscience, 2002
Amperometry and cyclic voltammetry are two electrochemical techniques that enable the detection o... more Amperometry and cyclic voltammetry are two electrochemical techniques that enable the detection of electroactive neurotransmitters that are released from single cells. These techniques have provided the first chemical view of the events that occur during exocytosis. This unit describes the isolation of several cell types known for their exocytotic properties, the fabrication and calibration of carbon fiber microelectrodes, as well as some of the equipment and software requirements for obtaining electrochemically generated data.
Synapse, 2002
The release and clearance of electrically evoked catecholamine (CA) in the ventral portion of the... more The release and clearance of electrically evoked catecholamine (CA) in the ventral portion of the bed nucleus of the stria terminalis (BSTV) in mouse brain slices was evaluated with fast‐scan cyclic voltammetry at carbon‐fiber microelectrodes (CFME). Uptake in this region was observed to be markedly slower than in the caudate putamen (CPu). Clearance rates were reduced in the BSTV in both norepinephrine transporter knockout (NET KO) and dopamine transporter knockout (DAT KO) mice when compared to results in wild‐type (WT) mice. However, uptake was faster in the BSTV in both the DAT and NET KO mice than in the CPu of DAT KO mice. This indicates that both transporters play a role in CA clearance in the BSTV. The transporters restrict extracellular CA to the general area of the BSTV, as revealed by the diminished signal as the CFME is moved sequentially further and further from the site where CA release is evoked. However, in slices from the DAT KOs and NET KOs, CA release could be obs...
Journal of Neurochemistry, 2008
Monitoring the release and uptake of catecholamines from terminals in weakly innervated brain reg... more Monitoring the release and uptake of catecholamines from terminals in weakly innervated brain regions is an important step in understanding their importance in normal brain function. To that end, we have labeled brain slices from transgenic mice that synthesize placental alkaline phosphatase (PLAP) on neurons containing tyrosine hydroxylase with antibody–fluorochrome conjugate, PLAP‐Cy5. Excitation of the fluorochrome enables catecholamine neurons to be visualized in living tissue. Immunohistochemical fluorescence with antibodies to tyrosine hydroxylase and dopamine β‐hydroxylase revealed that the PLAP labeling was specific to catecholamine neurons. In the prefrontal cortex (PFC), immunohistochemical fluorescence of the PLAP along with staining for dopamine transporter (DAT) and norepinephrine transporter (NET) revealed that all three exhibit remarkable spatial overlap. Fluorescence from the PLAP antibody was used to position carbon‐fiber microelectrodes adjacent to catecholamine ne...
Journal of Neurochemistry, 2004
: The vesicular contents in bovine chromaffin cells are maintained at high levels owing to the st... more : The vesicular contents in bovine chromaffin cells are maintained at high levels owing to the strong association of its contents, which is promoted by the low vesicular pH. The association is among the catecholamines, Ca2+, ATP, and vesicular proteins. It was found that transient application of a weak base, methylamine (30 mM), amphetamine (10 μM), or tyramine (10 μM), induced exocytotic release. Exposure to these agents was also found to increase both cytosolic catecholamine and intracellular Ca2+ concentration, as measured by amperometry and fura‐2 fluorescence. Amphetamine, the most potent amine with respect to evoking exocytosis, was found to be effective even in buffer with out external Ca2+ ; however, the occurrence of spikes was suppressed when BAPTA‐acetoxymethyl ester was used to complex intracellular Ca2+. Amphetamine‐induced spikes in Ca2+‐free medium were not suppressed by thapsigargin or ruthenium red, inhibitors of the sarco(endo)plasmic reticulum Ca2+‐ATPase and mitochondrial Ca2+ stores. Atomic absorption measurements of amphetamine‐ and methylamine‐treated vesicles reveal that intravesicular Ca2+ stores are decreased after a 15‐min incubation. Taken together, these data indicate that amphetamine and methylamine can disrupt vesicular stores to a sufficient degree that Ca2+ can escape and trigger exocytosis.
Journal of Biological Chemistry, 2000
Synapse, Apr 9, 2002
The release and clearance of electrically evoked catecholamine (CA) in the ventral portion of the... more The release and clearance of electrically evoked catecholamine (CA) in the ventral portion of the bed nucleus of the stria terminalis (BSTV) in mouse brain slices was evaluated with fast‐scan cyclic voltammetry at carbon‐fiber microelectrodes (CFME). Uptake in this region was observed to be markedly slower than in the caudate putamen (CPu). Clearance rates were reduced in the BSTV in both norepinephrine transporter knockout (NET KO) and dopamine transporter knockout (DAT KO) mice when compared to results in wild‐type (WT) mice. However, uptake was faster in the BSTV in both the DAT and NET KO mice than in the CPu of DAT KO mice. This indicates that both transporters play a role in CA clearance in the BSTV. The transporters restrict extracellular CA to the general area of the BSTV, as revealed by the diminished signal as the CFME is moved sequentially further and further from the site where CA release is evoked. However, in slices from the DAT KOs and NET KOs, CA release could be observed outside of the BSTV region during such experiments. These results show that the low rate uptake in the BSTV facilitates extrasynaptic diffusion of catecholamine, but that uptake still regulates and limits the range of the transmitter to the region. Slower clearance from the extracellular fluid allows the released CA to act as a volume transmitter and diffuse to distant sites within the region to exert its neurochemical action. Synapse 44:188–197, 2002. © 2002 Wiley‐Liss, Inc.
Clinical and Experimental Optometry, May 1, 2016
Current protocols in neuroscience, Feb 1, 2002
Amperometry and cyclic voltammetry are two electrochemical techniques that enable the detection o... more Amperometry and cyclic voltammetry are two electrochemical techniques that enable the detection of electroactive neurotransmitters that are released from single cells. These techniques have provided the first chemical view of the events that occur during exocytosis. This unit describes the isolation of several cell types known for their exocytotic properties, the fabrication and calibration of carbon fiber microelectrodes, as well as some of the equipment and software requirements for obtaining electrochemically generated data.
Annals of the New York Academy of Sciences, Oct 1, 2002
Contact Lens and Anterior Eye, Apr 1, 2016
Contact Lens and Anterior Eye, Jun 1, 2018
Annals of the New York Academy of Sciences, Oct 1, 2002
Carolina Digital Repository (University of North Carolina at Chapel Hill), 2000
Eye & Contact Lens-science and Clinical Practice, Nov 1, 2018
Objectives: Cosmetic contact lenses are increasingly popular because of their eye enhancing cosme... more Objectives: Cosmetic contact lenses are increasingly popular because of their eye enhancing cosmetic benefits. The pigment particles used in these lenses can impact lens surface characteristics. This article examines the surface characteristics and the differences between the clear and the pigmented regions among five limbal ring design lenses. Methods: Scanning electron microscopy was used to determine the location and depth of the pigment particles from the lens surface. The coefficient of friction (CoF) was determined with a Basalt-MUST microtribometer at clear and pigmented regions on either the front or the back surface. Atomic force microscopy was used to determine the surface roughness of each lens in root-mean-square (RMS) units at clear and pigmented regions. A linear mixed model for repeated measures was used for the analysis of the CoF and RMS roughness to compare all lenses. Results: Four lens types had pigments exposed on the surface and one lens type had pigment fully enclosed. The CoF difference between clear and pigmented regions were similar and not statistically significant (P¼0.0124) for the lens type with pigments enclosed, whereas the CoF difference for the other four lens types showed statistically significant difference (P,0.0001). Conclusions: Of the lenses tested here, cosmetic contact lenses with pigments enclosed in the lens matrix provided a more consistent surface between clear and pigmented regions compared with lenses that had exposed pigments.
Investigative Ophthalmology & Visual Science, 2020
Contact Lens and Anterior Eye, 2018
Eye & Contact Lens: Science & Clinical Practice, 2018
Objectives: Cosmetic contact lenses are increasingly popular because of their eye enhancing cosme... more Objectives: Cosmetic contact lenses are increasingly popular because of their eye enhancing cosmetic benefits. The pigment particles used in these lenses can impact lens surface characteristics. This article examines the surface characteristics and the differences between the clear and the pigmented regions among five limbal ring design lenses. Methods: Scanning electron microscopy was used to determine the location and depth of the pigment particles from the lens surface. The coefficient of friction (CoF) was determined with a Basalt-MUST microtribometer at clear and pigmented regions on either the front or the back surface. Atomic force microscopy was used to determine the surface roughness of each lens in root-mean-square (RMS) units at clear and pigmented regions. A linear mixed model for repeated measures was used for the analysis of the CoF and RMS roughness to compare all lenses. Results: Four lens types had pigments exposed on the surface and one lens type had pigment fully enclosed. The CoF difference between clear and pigmented regions were similar and not statistically significant (P¼0.0124) for the lens type with pigments enclosed, whereas the CoF difference for the other four lens types showed statistically significant difference (P,0.0001). Conclusions: Of the lenses tested here, cosmetic contact lenses with pigments enclosed in the lens matrix provided a more consistent surface between clear and pigmented regions compared with lenses that had exposed pigments.
Clinical and Experimental Optometry, 2016
Contact Lens and Anterior Eye, 2016
Current Protocols in Neuroscience, 2002
Amperometry and cyclic voltammetry are two electrochemical techniques that enable the detection o... more Amperometry and cyclic voltammetry are two electrochemical techniques that enable the detection of electroactive neurotransmitters that are released from single cells. These techniques have provided the first chemical view of the events that occur during exocytosis. This unit describes the isolation of several cell types known for their exocytotic properties, the fabrication and calibration of carbon fiber microelectrodes, as well as some of the equipment and software requirements for obtaining electrochemically generated data.
Synapse, 2002
The release and clearance of electrically evoked catecholamine (CA) in the ventral portion of the... more The release and clearance of electrically evoked catecholamine (CA) in the ventral portion of the bed nucleus of the stria terminalis (BSTV) in mouse brain slices was evaluated with fast‐scan cyclic voltammetry at carbon‐fiber microelectrodes (CFME). Uptake in this region was observed to be markedly slower than in the caudate putamen (CPu). Clearance rates were reduced in the BSTV in both norepinephrine transporter knockout (NET KO) and dopamine transporter knockout (DAT KO) mice when compared to results in wild‐type (WT) mice. However, uptake was faster in the BSTV in both the DAT and NET KO mice than in the CPu of DAT KO mice. This indicates that both transporters play a role in CA clearance in the BSTV. The transporters restrict extracellular CA to the general area of the BSTV, as revealed by the diminished signal as the CFME is moved sequentially further and further from the site where CA release is evoked. However, in slices from the DAT KOs and NET KOs, CA release could be obs...
Journal of Neurochemistry, 2008
Monitoring the release and uptake of catecholamines from terminals in weakly innervated brain reg... more Monitoring the release and uptake of catecholamines from terminals in weakly innervated brain regions is an important step in understanding their importance in normal brain function. To that end, we have labeled brain slices from transgenic mice that synthesize placental alkaline phosphatase (PLAP) on neurons containing tyrosine hydroxylase with antibody–fluorochrome conjugate, PLAP‐Cy5. Excitation of the fluorochrome enables catecholamine neurons to be visualized in living tissue. Immunohistochemical fluorescence with antibodies to tyrosine hydroxylase and dopamine β‐hydroxylase revealed that the PLAP labeling was specific to catecholamine neurons. In the prefrontal cortex (PFC), immunohistochemical fluorescence of the PLAP along with staining for dopamine transporter (DAT) and norepinephrine transporter (NET) revealed that all three exhibit remarkable spatial overlap. Fluorescence from the PLAP antibody was used to position carbon‐fiber microelectrodes adjacent to catecholamine ne...
Journal of Neurochemistry, 2004
: The vesicular contents in bovine chromaffin cells are maintained at high levels owing to the st... more : The vesicular contents in bovine chromaffin cells are maintained at high levels owing to the strong association of its contents, which is promoted by the low vesicular pH. The association is among the catecholamines, Ca2+, ATP, and vesicular proteins. It was found that transient application of a weak base, methylamine (30 mM), amphetamine (10 μM), or tyramine (10 μM), induced exocytotic release. Exposure to these agents was also found to increase both cytosolic catecholamine and intracellular Ca2+ concentration, as measured by amperometry and fura‐2 fluorescence. Amphetamine, the most potent amine with respect to evoking exocytosis, was found to be effective even in buffer with out external Ca2+ ; however, the occurrence of spikes was suppressed when BAPTA‐acetoxymethyl ester was used to complex intracellular Ca2+. Amphetamine‐induced spikes in Ca2+‐free medium were not suppressed by thapsigargin or ruthenium red, inhibitors of the sarco(endo)plasmic reticulum Ca2+‐ATPase and mitochondrial Ca2+ stores. Atomic absorption measurements of amphetamine‐ and methylamine‐treated vesicles reveal that intravesicular Ca2+ stores are decreased after a 15‐min incubation. Taken together, these data indicate that amphetamine and methylamine can disrupt vesicular stores to a sufficient degree that Ca2+ can escape and trigger exocytosis.
Journal of Biological Chemistry, 2000