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PubMed1998

Regulation of expression of galanin and galanin receptors in dorsal root ganglia and spinal cord after axotomy and inflammation.

Galanin can normally be detected only in a few dorsal root ganglion (DRG) neurons, but it is dramatically upregulated after peripheral nerve injury in both rat and monkey. Galanin is stored in large dense core vesicles, which after axotomy are often found close to the membrane of afferent nerve endings in the dorsal horn. In the monkey there is an increase in galanin in many nerve terminals in the superficial dorsal horn after axotomy, but such an increase is more difficult to detect in the rat. Galanin is also present in local dorsal horn neurons, where it is upregulated by peripheral inflammation. Both galanin-R1 and galanin-R2 receptor mRNAs are expressed in rat DRGs, mainly in, respectively, large and small DRG neurons. Galanin-R1 receptor mRNA is downregulated in DRG neurons after axotomy, and a small decrease in galanin-R2 receptor mRNA levels can also be seen. After peripheral tissue inflammation galanin-R1 receptor mRNA levels decrease and galanin-R2 receptor mRNA levels increase. The present results show that galanin and galanin receptors are present in sensory and local dorsal horn neurons and are regulated by nerve injury and inflammation. Galanin may therefore be involved in processing of pain information, primarily exerting analgesic effects. Whereas local dorsal horn neurons represent a defense system against inflammatory pain, we have proposed that a second defense system, against neuropathic pain, is intrinsic to DRG neurons.

Animals↗
PubMed2006

A short estrogen-responsive N-terminal galanin homologue found in rat brain and gut with antiserum raised against rat galanin(1-16).

Galanin-like peptide (GALP) is currently the only known galanin(1-29) homologue. However, three different galanin receptors, of which GalR3 exhibits comparatively low affinity for galanin(1-29), and molecular heterogeneity of immunoreactive galanin are arguments for presence of other endogenous galanin homologues. Since antibodies recognize three-dimensional structures of 3-5 amino acids in a peptide, we raised antibodies in rabbits against galanin(1-16) conjugated to bovine serum albumin, looking for the presence of endogenous N-terminal galanin homologues in rat tissues. The antiserum selected had 7,830 times higher avidity for galanin(1-16) compared to galanin(1-29). A single immunoreactive component with a Stokes radius of about 8 amino acids was found. Immunohistochemistry strongly suggested that this immunoreactivity is localised in the same neurons as galanin(1-29). Furthermore, its concentration was increased in response to estrogen treatment in the same brain regions as galanin(1-29), although not as rapidly. The present results indicate the presence of a novel endogenous N-terminal galanin homologue.

Animals↗
PubMed1988

Galanin hyperinnervates surviving neurons of the human basal nucleus of Meynert in dementias of Alzheimer's and Parkinson's disease: a hypothesis for the role of galanin in accentuating cholinergic dysfunction in dementia.

This study summarizes the findings from postmortem examination of the brains of 22 control cases without neurological deficit, 12 cases of senile dementia of the Alzheimer type (SDAT), and nine cases of Parkinson's disease (three without signs of intellectual deterioration, four with dementia, and two atypical with dementia nonresponsive to L-dopa treatment). The aim of this study was to find the similarities and differences in galanin innervation of the cholinergic basal nucleus neurons in these dementing disorders as compared with controls. Immunocytochemistry with antibodies against galanin peptide and against choline acetyltransferase was applied on perfused brain preparations. Galanin peptide is present in the basal nucleus of Meynert neuron networks in the normal human brain: in local circuit neurons, in a number of galanin/cholinergic neurons, and in a feedback circuit via collaterals) that terminate upon the cholinergic neuronal somata and dendrites. Thus, peptide galanin circuits could function as powerful modulators of the activities of basal nucleus cholinergic neurons, both within the basal forebrain and in their wider projections to the neocortex and amygdala. As galanin has been shown to inhibit cholinergic activity, this galanin network could suppress the activity of cholinergic neurons. In SDAT, there is a primary loss of cholinergic neurons compounded by a secondary reaction of the remaining cholinergic neurons to the terminal degeneration in the cortex. Galanin networks demonstrate an inverse relationship to the cholinergic cell loss. Galanin axons hypertrophy and hyperinnervate the remaining cholinergic neurons. In Parkinson's disease the loss of cholinergic neurons is accentuated by the presence of dementia: the hypertrophy of the galanin axonal networks on cholinergic neurons is dramatic in Parkinson's disease with dementia. These observations throw new light on the neurotransmitter bases for these dementias. Galanin controls cholinergic mechanisms in the basal nucleus of Meynert, and dementia is accompanied by augmentation of galanin innervation onto an already depressed population of cholinergic neurons, thus demonstrating an appreciable amount of plasticity even in aged brain. These findings suggest that the present therapy of cholinergic enhancement as a means to retard intellectual deterioration can by itself have little effect at best, in these dementias. The suppressive effect of galanin peptide has to be reduced or curtailed, perhaps concurrently with the treatment of the cholinergic deficit.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylcholine↗
PubMed2004

Ethanol intake is increased by injection of galanin in the paraventricular nucleus and reduced by a galanin antagonist.

Ethanol intake stimulates expression of galanin in several hypothalamic sites, including the paraventricular nucleus. Because injection of galanin in the paraventricular nucleus induces eating, we hypothesized that galanin might also affect ethanol intake. Rats were given ad libitum access to 4% ethanol for 4 weeks and assigned to one of two groups according to levels of ethanol consumption: high levels (>1.5 g/ kg/day) or low levels (<1.0 g/kg/day). In Experiment 1, galanin (1.0 nmol) or Ringer's solution was injected unilaterally into the paraventricular nucleus, with food and water absent during the first 4 h. Galanin significantly increased ethanol intake only in rats that drank high levels of ethanol. In Experiment 2, injection of galanin (0.5 and 1.0 nmol) in the paraventricular nucleus dose-dependently increased ethanol intake with food and water available. The higher dose was also effective in eliciting ethanol intake when tested with food and water absent. In Experiment 3, a test of receptor specificity was provided by injecting rats with the galanin antagonist M-40 (0.5 nmol) or Ringer's solution. Injection of M-40 in the paraventricular nucleus significantly decreased ethanol consumption. In Experiment 4, an anatomic control, with galanin injected 2 mm dorsal to the paraventricular nucleus in the same animals, caused no change in ethanol intake. In conclusion, injection of galanin in the paraventricular nucleus, at a dose known to induce feeding, acted by means of a galanin receptor to potentiate intake of 4% ethanol, even with food and water available as alternate sources of calories and fluid, respectively. Because ethanol can increase expression of galanin mRNA in the paraventricular nucleus, this could set the stage for a positive feedback loop between galanin and ethanol intake.

Alcohol Drinking↗
PubMed1996

Effect of three galanin antagonists on the pressor response to galanin in the Cane toad, Bufo marinus.

Galanin is a neuropeptide that causes a marked pressor response in several non-mammalian vertebrate species, and some marsupials. In this study, the effect of three galanin antagonists were tested on the pressor response to an intravenous dose (6.3 nmol/kg) of porcine galanin in anaesthetised Cane toads, Bufo marinus. Antagonists were injected at either 20 or 50 times the molar dose (x MD) of galanin. The antagonist, C7 (Galanin 1-13-spantide) reduced the pressor effect of galanin by 32.2 +/- 6.0% when delivered at 20 x MD (n = 4) and by 42.9 +/- 15.7% when delivered at 50 x MD (n = 4) of galanin, the response recovering within 30 min. A second antagonist, M32a (Galanin 1-13-NPY 24-36) had no effect on the pressor response to galanin at 20 x MD (n = 4), but significantly reduced the pressor effect by 54.8 +/- 6.4% at 50 x MD (n = 5), which also recovered within 30 min. Administration of a third antagonist, galantide or M15 (Galanin 1-13-Substance P5-11), resulted in a profound drop in blood pressure, and did not affect the response to galanin at either dose. In conclusion, C7 and M32a are effective, short-term antagonists of the blood pressure effects of galanin in the toad.

Animals↗
PubMed2000

Effects of centrally administered galanin (1-16) on galanin expression in the rat hypothalamus.

In the rat hypothalamic magnocellular neurons, galanin coexists with vasopressin and might be involved in hydro-osmotic regulation. In the present study, we investigated the ability of galanin to also regulate the osmotically stimulated expression of galanin itself in hypothalamic magnocellular neurons. Ten minutes after galanin injection, galanin mRNA rate decreased in salt-loaded rats whereas the level of galanin immunoreactivity increased. Both effects were suppressed by the injection of a galanin antagonist together with galanin. Moreover, electron microscope studies demonstrated synaptic contacts between galanin-containing fibers and magnocellular neurons. Galanin may exert inhibitory roles in the regulation of magnocellular neurons. However, galanin and vasopressin expression displayed differences upon galanin injection. Possible mechanisms underlying these discrepancies are further discussed.

Animals↗
PubMed2004

Antinociceptive effects of galanin in the rat tuberomammillary nucleus and the plasticity of galanin receptor 1 during hyperalgesia.

Although the tuberomammillary nucleus (TM) is well defined in terms of anatomy and neurochemistry, little is known about its function in nociceptive modulation. There was an abundance of galanin-immunoreactive fibers in the TM, and galanin has been implicated in pain processing. The present study assessed the role of galanin in the modulation of nociception in the TM of rats. Intra-TM injection of galanin dose-dependently increased the hindpaw withdrawal latency of rats to a noxious thermal stimulus, indicating an antinociceptive role of galanin in the TM. The antinociceptive effect of galanin was blocked by a subsequent intra-TM injection of galantide, a putative galanin receptor antagonist, suggesting that the antinociceptive effect of galanin is mediated by galanin receptors. Moreover, there was abundant galanin receptor 1 (GalR1) in the TM, and the number of GalR1-positive neurons in the ipsilateral TM increased significantly after unilateral loose ligation of the sciatic nerve compared with the contralateral TM or the TM of intact rats. However, the number of GalR1-positive neurons was not significantly altered by carrageenan-induced inflammation, in either the ipsilateral or the contralateral TM. The results suggest that galanin and GalR1 in the TM may play important roles in pain regulation.

Analysis of Variance↗
PubMed1993

Galanin receptor antagonists M40 and C7 block galanin-induced feeding.

Two peptide antagonists of the galanin receptor, M40 (galanin[1-13]-Pro-Pro-[Ala-Leu]2-Ala amide) and C7 (galanin[1-13]-spantide amide), significantly inhibited galanin-induced consumption of a palatable wet cookie mash, when microinjected intraventricularly to satiated rats. Antagonists were effective at doses equimolar to or less than the active doses of galanin. Feeding induced by an overnight fast was not significantly different in rats microinjected with saline as compared to M40 or C7, at doses which inhibited galanin-induced feeding. The activity of the chimeric compound, C7, did not appear to be linked to the properties of its C-terminal spantide-like sequence, as C7 did not induce barrel rolling at doses which inhibited galanin-induced feeding. The IC50 for displacement of 125I-[Tyr26]-porcine galanin 1-29 binding in rat hypothalamic membranes was 15 nM for M40, and 0.2 nM for C7, as compared to 0.8 nM for unlabelled porcine galanin(1-29). These two structurally different galanin antagonists, both demonstrating antagonist activity in vivo in awake, behaving rats, provide promising tools for further analyses of the functional activity of galanin in the mammalian brain.

Amino Acid Sequence↗
PubMed1994

Activation of galanin pathways across puberty in the male rat: assessment of regional densities of galanin binding sites.

Galanin-like immunoreactivity and galanin messenger RNA levels increase across puberty in neurons of gonadal steroid-dependent brain nuclei. We hypothesized that this activation and the associated increase in endogenous galanin release would result in changes across puberty in both galanin binding density and the level of receptor occupancy. Here we have assessed the density of galanin binding sites in several brain regions of prepubertal and adult male rats with or without GTP to induce dissociation of endogenous galanin from its binding sites. The developmental changes in the level of receptor occupancy were used as an indirect measure of changes in neuropeptide release from galanin expressing neurons. In standard binding conditions (buffer preincubation), 125I-labeled galanin binding showed a generalized decline in adult brains (34-68%) compared with prepubertal levels in most regions of the telencephalon and diencephalon. Following preincubation with 10(-5) M GTP, galanin binding showed a dramatic increase in most regions of the adult (152-504%) and several regions of the prepubertal brain (132-245%) over their standard binding levels. However, this increase was greatest in adult animals. Finally, although preincubation of brain slices with GTP eliminated most of the apparent age-related differences observed in standard binding conditions, several brain regions of the adult brain continued to show a significant reduction (38-76%) in 125I-labeled galanin binding compared with prepubertal animals. Only one region, the lateral preoptic area, exhibited enhanced 125I-labeled galanin binding in adult (160%) compared with prepubertal brain after GTP preincubation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1997

Ultrastructural localization of galanin and galanin receptors in the guinea pig median eminence.

The aim of this work was to compare the localization of galanin and galanin receptors in the guinea pig median eminence at the light and electron microscopic level. Concerning galanin the highest labeling was shown in the external part of the median eminence. At the ultrastructural level, galanin immunoreactivity was observed only in nerve terminals containing granular vesicles of approximately 120 nm in diameter. Light microscopic autoradiographs of semithin sections exhibited a moderate labeling in the external part of the median eminence. Galanin receptors were labeled in vitro on semithin sections (2 microm) using the highly specific radioligand [125I]galanin. Ultrastructural data showed that most of galanin binding sites overlaid membrane appositions between nerve terminals and also between nerve terminal and tanycyte. By considering the percentages in the distribution of the binding it appeared that galanin receptors were located on some nerve ending membranes. Our observations were not really in favor of a presence of receptors in tanycytes. The presence of galanin nerve endings in the external part suggests that like in the rat the peptide may have a direct hypophysiotrophic role. In contrast, the occurrence of numerous binding sites gives additional arguments in favor of a local action (paracrine and/or autocrine) of galanin occurring via galanin receptors located essentially on the pericapillary nerve terminals in the guinea pig median eminence.

Animals↗
PubMed1989

N-terminal galanin-(1-16) fragment is an agonist at the hippocampal galanin receptor.

The galanin N-terminal fragment [galanin-(1-16)] has been prepared by solid-phase synthesis and by enzymic cleavage of galanin by endoproteinase Asp-N. This peptide fragment displaced 125I-labeled galanin in receptor autoradiography experiments on rat forebrain and spinal cord and in equilibrium binding experiments from high-affinity binding sites in the ventral hippocampus with an IC50 of approximately 3 nM. In tissue slices of the same brain area, galanin-(1-16), similarly to galanin, inhibited the muscarinic agonist-stimulated breakdown of inositol phospholipids. Upon intracerebroventricular administration, galanin-(1-16) (10 micrograms/15 microliters) also inhibited the scopolamine (0.3 mg/kg, s.c.)-evoked release of acetylcholine, as studied in vivo by microdialysis. Substitution of [L-Trp2] for [D-Trp2] resulted in a 500-fold loss in affinity as compared with galanin-(1-16). It is concluded that, in the ventral hippocampus, the N-terminal galanin fragment [galanin-(1-16)] is recognized by the galanin receptors controlling acetylcholine release and muscarinic agonist-stimulated inositol phospholipid breakdown as a high-affinity agonist and that amino acid residue [Trp2] plays an important role in the receptor-ligand interactions.

Animals↗
PubMed1990

Activity of centrally administered galanin fragments on stimulation of feeding behavior and on galanin receptor binding in the rat hypothalamus.

Synthetic fragments of galanin 1-29 were administered intraventricularly or into the paraventricular nucleus of the hypothalamus for analysis of the critical amino acid sequence necessary to stimulate feeding behavior in rats. Galanin 1-29 and galanin fragment 1-16 significantly increased feeding at doses of 6 nmol microinjected into the lateral ventricles and 1 nmol microinjected into the hypothalamus. There was no significant effect of D-TRP2 galanin 1-16 microinjected into the hypothalamus, and no significant effect of galanin fragments 1-9, 10-20, 12-29, 17-29, or 21-29 microinjected intraventricularly, on food consumption. Synthetic fragments of galanin 1-29 were assayed for displacement of 125I-galanin 1-29 binding to rat hypothalamic membranes. The efficacies of the galanin fragments in the feeding paradigm were consistent with the relative affinities of these fragments for the hypothalamic galanin receptor in equilibrium binding experiments. The first 16 N-terminal amino acids appear to contain galanin agonist activity on increasing food consumption and to bind to the galanin receptor in the rat hypothalamus.

Animals↗
PubMed1998

Pharmacological and biochemical characterization of a recombinant human galanin GALR1 receptor: agonist character of chimeric galanin peptides.

The galanin neuropeptide system is widely distributed throughout the brain and periphery and is thought to play a role in feeding, pain and reproduction. To evaluate the human galanin receptor 1 as a potential therapeutic target, we fully characterized its interaction with several galanin-like peptides. The human galanin receptor 1 receptor was stably expressed using an episomal system in human embryonic kidney 293E cells. Saturation isotherms using 125I-human galanin revealed two distinct populations of receptor affinity states in membranes and whole cells with picomolar and nanomolar affinities at the high- and low affinity states, respectively. A scintillation proximity assay revealed that 125I-human galanin binding in membranes reached steady-state within 2 to 2.5 hr; however, only 50% of galanin radiolabel dissociated from the receptors by excess galanin or guanosine 5'-O-3-thiotriphosphate even after 20 hr. In contrast, galanin binding in whole cells was completely reversible within 1 hr. Competition binding assays showed that galanin-like peptides bound with picomolar affinities in membranes and whole cells. These peptides behaved as full agonists as determined by the inhibition of forskolin-stimulated cyclic 3'5'-adenosine monophosphate production and the stimulation of guanosine 5'-O-(3-[35S]thiotriphosphate binding. The agonist profile of M40, a representative chimeric peptide, was found not to be the result of receptor reserve because receptor inactivation by partial alkylation experiments confirmed its full intrinsic efficacy under conditions of a "zero" reserve state. These observations suggest that the antagonist effects in vivo of M40, and perhaps other chimeric peptides, are not mediated via direct interactions with the galanin receptor 1 receptor.

Alkylation↗
PubMed1991

Hypothalamic degradation of galanin(1-29) and galanin(1-16): identification and characterization of the peptidolytic products.

The degradation of the neuropeptide galanin(1-29) and its fully active synthetic N-terminal fragment galanin(1-16) in hypothalamic tissue, where these peptides potently affect feeding behaviour, is studied. Galanin(1-29) had a half-life of 100 min while galanin(1-16) had a half-life of 28 min when incubated with a hypothalamic membrane preparation. The putative sites of peptidolytic cleavage of the active N-terminal fragment galanin(1-16) were determined as being between amino acids Leu4 and Asn5, between Asn5 and Ser6, and between His14 and Ala15, respectively. The synthetic analogs of galanin(1-16) where Leu4, Asn5 or Ser6 was substituted by Ala were all more stable to peptidolysis; [Ala4]galanin(1-16) had a half-life of 55 min. Cleavage of the galanin(1-16) between His14-Ala15 yields a ligand-galanin(1-14) which binds to the receptor with high affinity (KD approximately 10(7) M), while cleavage at amino acid residues Leu4, Asn5 and Ser6 results in inactive peptide fragments with affinities for the galanin receptor below 10(-4) M. The enzyme(s) responsible for degradation of galanin were identified as endopeptidase(s), which were partially inhibited by bacitracin (1 mg/ml) by up to 50%, but not significantly by EDTA (1 mM), phosphoramidon (1 microM), phenylmethylsulfonyl fluoride, (100 microM) or aprotinin (10 micrograms/ml).

Amino Acid Sequence↗
PubMedDate not supplied

Deficits in trace cued fear conditioning in galanin-treated rats and galanin-overexpressing transgenic mice.

Galanin inhibits the release of several neurotransmitters and produces performance deficits in a variety of spatial and aversive learning and memory tasks. The experiments in this study investigated the role galanin has in emotional learning and memory using a standard delay cued and contextual fear conditioning task. Rats were administered galanin into the lateral ventricles before training, and scored for freezing behavior in the same context and in a novel context with and without an auditory cue (CS) that had been paired previously with an aversive stimulus (US). Galanin-overexpressing transgenic mice were tested in an identical behavioral protocol. The galanin-administered rats and the transgenic mice were not significantly different from their respective controls on this task. A more challenging trace cued and contextual fear conditioning procedure was administered to separate groups of galanin-treated rats and galanin-overexpressing transgenic mice. Subjects were trained with the same CS and US, however, a 2.5-sec delay was inserted between CS offset and US onset. Following the trace conditioning, rats administered galanin and mice overexpressing galanin both exhibited significantly less freezing to the CS in the novel context as compared with their control groups. These results indicate that the observed disruption of cued fear conditioning was specific to the more difficult trace conditioning task. These findings are the first demonstration that galanin impairs performance on an emotional memory task and support the hypothesis that galanin-induced deficits are specific to more difficult cognitive tasks.

Acoustic Stimulation↗
PubMed1989

On the nature of the galanin action on the endocrine pancreas: studies with six galanin fragments in the perfused dog pancreas.

Galanin, a 29 amino acid peptide, inhibits insulin and somatostatin secretion from the isolated, perfused dog pancreas. To assess the nature of the influences of galanin on the endocrine pancreas, we examined the effects of porcine galanin and six different galanin analogues at the equimolar concentration of 1 nmol/l on the hormone release from the isolated, perfused dog pancreas. It was found that galanin2-29 (by 75 +/- 4%), like the native galanin1-29 (by 90 +/- 3%) potently inhibited insulin secretion (p less than 0.001). In contrast, galanin3-29 did not significantly affect insulin secretion. This indicates that removal of the two N-terminal amino acids markedly reduces the potency of galanin. Also, the replacement of the amino acid number 2 (Trp) by Tyr or Phe was followed by a loss of the insulin lowering effect of galanin at this dose level. Likewise, galanin10-29 had no significant effect on insulin secretion. In contrast, the C-terminally deleted galanin1-15 significantly inhibited insulin secretion (by 24 +/- 5%; p less than 0.01), though with a lower potency than did native galanin (p less than 0.05). Consequently, the C-terminal end of galanin is also of importance for the effect. Somatostatin secretion was inhibited by galanin (p less than 0.001), but not by any of the other investigated peptides. Glucagon secretion was not affected by galanin. It is concluded that the two N-terminal amino acids of galanin are essential for the inhibitory action on the insulin secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed2006

Galanin and galanin-like peptide modulate neurite outgrowth via protein kinase C-mediated activation of extracellular signal-related kinase.

The neuropeptide galanin is widely distributed in the central nervous system and plays a role in a number of processes in the adult brain. Galanin also has neurotrophic effects in the developing nervous system and after nerve injury. The current study investigated the mechanism by which galanin promotes neurite outgrowth in the neuronal cell line PC12 and in neurospheres derived from adult hippocampal progenitor cells. We demonstrated that galanin can induce extracellular signal-related kinase (ERK) phosphorylation transiently in a concentration-dependent manner in neurons. Galanin-like peptide, which is thought to signal primarily through the GalR2 receptor subtype, induced ERK phosphorylation with similar kinetics to galanin. In functional studies, the ability of galanin and galanin-like peptide to induce neurite outgrowth was dependent on activation of both protein kinase C and ERK. This study identified a novel physiological role for galanin-induced ERK phosphorylation and identified ERK and protein kinase C as important signaling components in the galanin-mediated modulation of neurite outgrowth.

Animals↗
PubMed1990

Distribution of Galanin mRNA Containing Cells and Galanin Receptor Binding Sites in Human and Rat Hypothalamus.

The distribution of cells containing galanin mRNA and that of galanin receptor binding sites were investigated using in situ hybridization histochemistry and receptor autoradiography in male rat hypothalamus and in postmortem hypothalamic tissues from control human brains. Oligonucleotide probes labelled with 32P were used for hybridization experiments. The specificity of the hybridization signal was ascertained using several probes, competition assays and Northern blot analysis. High levels of hybridization were found in the paraventricular, supraoptic and arcuate nuclei of rat and human hypothalamus. Human intermediate nuclei and scattered cells of the posterior perifornical nucleus also contained galanin mRNA. Galanin mRNA was also found in the dorsomedial nucleus of the rat. The distribution of galanin receptor sites was investigated by receptor autoradiography using 125I-labelled porcine galanin. The specificity of the binding was assessed by competition with different neuropeptides. While galanin blocked the binding at nanomolar concentrations, the other neuropeptides examined were ineffective at 10-7 M concentrations. The highest densities of galanin binding sites were seen in the preoptic area, ventromedial and lateral nuclei, of rat and human hypothalamus. In contrast, very low densities of binding sites were observed in the paraventricular, supraoptic and arcuate nuclei. Our results show that the distribution of neurons expressing galanin is complementary to that of galanin receptors in the rat and human hypothalamus. This suggests that receptors for galanin are not located on the cell bodies of galaninergic neurons, but are probably presynaptic on or postsynaptic to the processes of these cells.

Journal Article↗