The presence and possible role of a galanin-like peptide in the mudpuppy heart

Parsons, Rodney L.; Neel, Darcy S.; Konopka, Lukasz M.; McKeon, Tina Williams

doi:10.1016/0306-4522(89)90146-2

Cited by 36 publications

(14 citation statements)

References 20 publications

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“…[3][4][5] In 1989 we reported that a neuropeptide antigenically very similar to mammalian galanin was present in neurons and fibers within mudpuppy cardiac tissues. 8 Later studies demonstrated that the distribution of this galanin-like neuropeptide in different tissues of the mudpuppy was similar to that reported for other species. 9 We have developed the muda…”

supporting

confidence: 65%

Galanin Activates an Inwardly Rectifying Potassium Conductance and Inhibits a Voltage‐Dependent Calcium Conductance in Mudpuppy Parasympathetic Neurons ^a

Parsons¹,

Mulvaney²,

Merriam³

1998

Annals of the New York Academy of Sciences

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Galanin-induced activation of an inwardly rectifying membrane potassium (K+) current and inhibition of barium current (IBa) were studied using whole cell voltage clamp recording techniques in parasympathetic neurons dissociated from the mudpuppy cardiac ganglion. Both activation of the K+ current and inhibition of IBa were concentration-dependent with an EC50 (or IC50) of approximately 35 nM and approximately 0.4 nM, respectively. Both actions of galanin were eliminated by pretreatment with pertussis toxin, which suggested involvement of Gi/Go protein activation. Galantide antagonized the galanin-induced activation of K+ current with an IC50 equal to 4 nM. By contrast, galantide, by itself, inhibited IBa with an EC50 equal to 16 nM. Another galanin analog, M40, primarily antagonized the galanin-induced activation of K+ current, but in some cells, M40 also acted as a weak agonist. M40, like galantide, inhibited IBa. The NH2-terminal fragment galanin-(1-16) activated the K+ current and inhibited IBa, indicating that the first 16 amino acids of the galanin peptide were sufficient for both actions. In summary, it is postulated that the effects of galanin on mudpuppy parasympathetic neurons might be mediated by activation of two different subtypes of galanin receptor, one that regulates membrane K+ conductance and a second that modulates calcium conductance.

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supporting

confidence: 65%

Galanin Activates an Inwardly Rectifying Potassium Conductance and Inhibits a Voltage‐Dependent Calcium Conductance in Mudpuppy Parasympathetic Neurons ^a

Parsons¹,

Mulvaney²,

Merriam³

1998

Annals of the New York Academy of Sciences

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“…In many preparations, the SIF cells may contain monoamines as well as neuropeptides or other putative neurotransmitter/neuromodulator substances which could be used to mediate specific functions within ganglia (Williams & Jew, 1983). The SIF cells in the mudpuppy cardiac ganglion also contain a number of different bioactive substances such as a substance P-like peptide, a galanin-like peptide, and serotonin in addition to a catecholamine (Neel & Parsons, 1986;Parsons et al 1988). However, application of only galanin has been reported to have a direct effect on the parasympathetic neurones ).…”

Section: Discussionmentioning

confidence: 99%

“…These small SIF cells have processes which can extend for 50-100 /um and make synaptic contact with postganglionic neurones (McMahan & Purves, 1976;Neel & Parsons, 1986; R. Kriebel, A. Angel & R. L. Parsons, unpublished observations). Although the presence of the SIF cells in this preparation was demonstrated many years ago, the function of these cells is still not established (McMahan & Purves, 1976 (Neel & Parsons, 4986;Parsons, Neel, McKeon & Carraway, 1987;Parsons, Neel, Konopka & McKeon, 1988). However, to date, of these putative neurotransmitter/neuromodulator substances contained in many SIF cells, only the twenty-nine-amino acid neuropeptide, galanin, has been found to directly affect the membrane potential of postganglionic parasympathetic neurones in the mudpuppy cardiac ganglion ; R. L. Parsons, unpublished observations).…”

Section: Introductionmentioning

confidence: 99%

Galanin‐induced hyperpolarization and decreased membrane excitability of neurones in mudpuppy cardiac ganglia.

Konopka

McKeon

Parsons

1989

The Journal of Physiology

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SUMMARY1. Membrane hyperpolarization and decreased excitability produced by galanin were investigated in vitro on parasympathetic postganglionic neurones in the cardiac ganglion of the mudpuppy, Necturus maculosus.2. Galanin produced a slowly developing hyperpolarization which, in 2-5 mM-KCl, reversed at -105-4 + 2-7 mV. The reversal potential was shifted by 38-7 + 4-9 mV following a fourfold elevation of the extracellular potassium concentration.3. Galanin inhibited action potential firing in spontaneously active neurones and decreased the number of spikes in a train produced by long (500-680 ms) depolarizing current pulses. Both effects were independent of the galanin-induced hyperpolarization.4. Galanin increased the threshold for spike generation, prolonged the spike hyperpolarizing after-potential and decreased the maximum rate of rise, amplitude and maximum rate of fall of the sodium spike. These effects occurred independently of the galanin-induced hyperpolarization.5. Galanin decreased the amplitude and duration of TTX-insensitive spikes initiated in cells maintained in a solution containing 9 mM-calcium, 20 mM-TEA and 1-5 uM-TTX.6. These results suggest that a galanin-like peptide may act as an inhibitory transmitter in the mudpuppy cardiac ganglion.

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“…Mounting experimental evidence on the cardiac ganglia has challenged this convention Hardwick, Mawe, & Parsons, 1995;Parsons, Neel, McKeon, & Carraway, 1987). In addition, various neural modulators and transmitters have been found in cardiac ganglia (Neel & Parsons, 1986a;Parsons, Neel, Konopka, & McKeon, 1989;Sosunov, Hassall, Loesch, Turmaine, & Burnstock, 1996;Sosunov et al, 1997;Steele, Gibbins, Morris, & Mayer, 1994). These neuromodulators could participate in the local re ex through a variety of extra-and intracellular signaling mechanisms.…”

Section: Introductionmentioning

confidence: 95%

Analysis and Neuronal Modeling of the Nonlinear Characteristics of a Local Cardiac Reflex in the Rat

2001

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Previous experimental results have suggested the existence of a local cardiac reflex in the rat. In this study, the putative role of such a local reflex in cardiovascular regulation is quantitatively analyzed. A model for the local reflex is developed from anatomical experimental results and physiological data in the literature. Using this model, a systems-level analysis is conducted. Simulation results indicate that the neuromodulatory mechanism of the local reflex attenuates the nonlinearity of the relationship between cardiac vagal drive and arterial pressure. This behavior is characterized through coherence analysis. Furthermore, the modulation of phase-related characteristics of the cardiovascular system is suggested as a plausible mechanism for the nonlinear attenuation. Based on these results, it is plausible that the functional role of the local reflex is highly robust nonlinear compensation at the heart, which results in less complex dynamics in other parts of the reflex.

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The presence and possible role of a galanin-like peptide in the mudpuppy heart

Cited by 36 publications

References 20 publications

Galanin Activates an Inwardly Rectifying Potassium Conductance and Inhibits a Voltage‐Dependent Calcium Conductance in Mudpuppy Parasympathetic Neurons ^a

Galanin Activates an Inwardly Rectifying Potassium Conductance and Inhibits a Voltage‐Dependent Calcium Conductance in Mudpuppy Parasympathetic Neurons ^a

Galanin‐induced hyperpolarization and decreased membrane excitability of neurones in mudpuppy cardiac ganglia.

Analysis and Neuronal Modeling of the Nonlinear Characteristics of a Local Cardiac Reflex in the Rat

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The presence and possible role of a galanin-like peptide in the mudpuppy heart

Cited by 36 publications

References 20 publications

Galanin Activates an Inwardly Rectifying Potassium Conductance and Inhibits a Voltage‐Dependent Calcium Conductance in Mudpuppy Parasympathetic Neurons a

Galanin Activates an Inwardly Rectifying Potassium Conductance and Inhibits a Voltage‐Dependent Calcium Conductance in Mudpuppy Parasympathetic Neurons a

Galanin‐induced hyperpolarization and decreased membrane excitability of neurones in mudpuppy cardiac ganglia.

Analysis and Neuronal Modeling of the Nonlinear Characteristics of a Local Cardiac Reflex in the Rat

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Galanin Activates an Inwardly Rectifying Potassium Conductance and Inhibits a Voltage‐Dependent Calcium Conductance in Mudpuppy Parasympathetic Neurons ^a

Galanin Activates an Inwardly Rectifying Potassium Conductance and Inhibits a Voltage‐Dependent Calcium Conductance in Mudpuppy Parasympathetic Neurons ^a