Showing 1 - 8 of 8 Items
The effects of manipulated afterload pressure on heartbeat frequency, active force, and cardiac output of the American lobster, Homarus americanus Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2019-05-01
Creator: Gina Fickera
Access: Access restricted to the Bowdoin Community
Role of the Dopamine Subtype 1 Receptor (D1R) Modulation of the Ih Current in Rhythmic Spinal Mammalian Motor Networks Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2025-06-01
Date: 2022-01-01
Creator: Grace Soeun Lee
Access: Access restricted to the Bowdoin Community
Efficacy of Curcumin as a Neuroprotectant Against Dibutyl Phthalate (DBP) - Induced Effects on the Mammalian Spinal Cord Locomotor Neural Network This record is embargoed.
- Embargo End Date: 2027-05-15
Date: 2024-01-01
Creator: Eliza Schotten
Access: Embargoed
The modulation of calcium-activated potassium channels for the stabilization of mammalian spinal locomotor activity This record is embargoed.
- Embargo End Date: 2026-12-14
Date: 2023-01-01
Creator: Hattie Sargent Slayton
Access: Embargoed
The Regulatory Effect of High Dopamine on the Hyperpolarization-Activated Inward Current (Ih) and its Role in the Stability and Rhythmicity of Mammalian Locomotor Neural Networks Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2025-06-01
Date: 2022-01-01
Creator: Abigail Raymond
Access: Access restricted to the Bowdoin Community
Differential modulation of the Homarus americanus cardiac neuromuscular system across cell types and among neuropeptide isoforms Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2020-01-01
Creator: Emily R Oleisky
Access: Access restricted to the Bowdoin Community
Responses of central pattern generators in the American lobster STNS to multiple members of a novel neuropeptide family
Date: 2020-01-01
Creator: Benjamin Harley Wong
Access: Open access
- Neuropeptides are important modulators of neural activity, allowing neural networks, such as the central pattern generators (CPGs) that control rhythmic movements, to alter their output and thus generate behavioral flexibility. Isoforms of a neuropeptide family vary in physical structure, allowing potentially distinct functional neuromodulatory effects on CPG systems. While some familial neuropeptide isoforms can differentially affect a system, others in the same family may elicit indistinguishable effects. Here, we examined the effects elicited by members of a novel family of six peptide hormone isoforms (GSEFLamides: I-, M-, AL-, AM-, AV-, and VM-GSEFLamide) on the pyloric filter and gastric mill CPGs in the stomatogastric nervous system (STNS) of the American lobster, Homarus americanus. Recent unpublished work from the Dickinson lab found that five of the six GSEFLamides elicited similar increases in contraction amplitude when perfused through the isolated lobster heart, while one (AVGSEFLamide) had virtually no effect. Using extracellular recordings, we found the pattern of GSEFLamide effects on the STNS gastric mill to be similar to the pattern observed in the lobster cardiac system; the gastric mill circuit was fairly consistently activated by all isoforms except AVGSEFLamide. The intrinsically active pyloric pattern was also significantly enhanced by three out of five peptide isoforms, and nearly significantly enhanced by two more, but was likewise non-responsive to AVGSEFLamide. While the reason AVGSEFLamide had no effect on either pattern is unknown, the similar phenomenon noted in the isolated whole heart potentially indicates that this isoform lacks any function in the lobster.
Modulation of the stretch feedback pathway in the cardiac neuromuscular system of the American lobster, Homarus americanus
Date: 2024-01-01
Creator: Karin van Hassel
Access: Open access
- The cardiac ganglion (CG) is a central pattern generator, a neural network that, when activated, produces patterned motor outputs such as breathing and walking. The CG induces the heart contractions of the American lobster, Homarus americanus, making the lobster heart neurogenic. In the American lobster, the CG is made up of nine neurons: four premotor pacemaker neurons that send signals to five motor neurons, causing bursts of action potentials from the motor neurons. These bursts cause cardiac muscle contractions that vary in strength based on the burst duration, frequency, and pattern. The activity of the CG is modulated by feedback pathways and neuromodulators, allowing for flexibility in the CG’s motor output and appropriate responses to changes in the animal’s environment. Two feedback pathways modulate the CG motor output, the excitatory cardiac muscle stretch and inhibitory nitric oxide feedback pathways. Despite our knowledge of the modulation of the CG by feedback pathways and neuromodulators separately, little is known about how neuromodulators influence the sensory feedback response to cardiac muscle stretch. I found one neuromodulator to modulate each phase of the stretch response differently, one neuromodulator to generally not affect the stretch response, and three neuromodulators to suppress the stretch response. These results suggest neuromodulators can act to produce flexibility in a CPG’s motor output, allowing the system to respond appropriately to changes in an organism’s environment, and allow for variation in CPG responses to different stimuli.