Pharmacology seminars

Cluster headache is a brain disorder dominated clinically by dreadful episodes of excruciating pain with a circadian pattern and most often focused in bouts with circannual periodicity. As we have understood its neurobiology new therapies, including those directed at calcitonin gene-related peptide, are helpful improve the lives of sufferers.

Pathogenic variants in HCN1 are associated with severe developmental and epileptic encephalopathies (DEE). We have engineered the Hcn1 M294L heterozygous knock-in (Hcn1M294L) mouse which is a homolog of the de novo HCN1 M305L recurrent pathogenic variant. The mouse recapitulates the phenotypic features of patients including having spontaneous seizures and a learning deficit. In this talk I will present experimental work that probes the molecular and cellular mechanisms underlying hyper-excitability in the mouse model. This will include testing the efficacy of currently available antiepileptic drugs and a novel precision medicine approach. I will also briefly touch on how disease biology can give insights into the biophysical properties of HCN channels.

This seminar will focus on the extraordinary shift in migraine research during the last 4 decades with the discovery of the trigeminovascular system (TVS) and it’s major impact on pathophysiology and treatment. Compelling evidence supporting the importance of TVS, cortical spreading depression and parameningeal inflammation will be explored as will the implications of newly discovered microvascular channels within the meninges on an attack.

Many studies have investigated the major glutamatergic inputs to the cerebellum, mossy fibres and climbing fibres, however far less is known about its neuromodulatory inputs. In particular, anatomical studies have described cholinergic input to the cerebellum, yet little is known about its role(s). In this talk, I will present our recent findings which demonstrate that manipulating acetylcholine receptors in the cerebellum causes effects at both a cellular and behavioural level. Activating acetylcholine receptors alters the intrinsic properties and synaptic inputs of cerebellar output neurons, and blocking these receptors results in deficits in a range of behavioural tasks.

In this presentation I will describe how the CGRP project started and culminated in the development of gepants and mAbs for successful therapy. The outstanding question regarding the preponderance of female migraineurs also remains. I will present views on the reason behind this and suggest that understanding the hormonal influence will pave the way to alleviating hormone related migraine.

Pain has both a sensory and emotional component and is driven by activation of sensory neurones called nociceptors that are tuned to detect noxious stimuli in a process called nociception. Although nociception functions as a detect and protect mechanism. and is found in many organisms, this system becomes dysregulated in a number of conditions where chronic pain presents as a key symptom, for example osteoarthritis. Nociceptors do not innervate empty space though and do not act alone. Going beyond the neurone, other cell types, such as fibroblast-like synoviocytes interact with and modify the function of nociceptors, which is likely a key contributor to the chronification of pain. In this talk, I will look at how combining pre-clinical mouse work with human tissue and genetics might provide a way to accelerate new analgesics from bench to bedside, giving examples from our work in joint pain, bowel pain and labour pain.

Tuberous sclerosis complex (TSC) and focal cortical dysplasia type II (FCDII) are caused by mutations in mTOR pathway genes leading to mTOR hyperactivity, focal malformations of cortical development (fMCD), and seizures in 80-90% of the patients. The current definitive treatments for epilepsy are surgical resection or treatment with everolimus, which inhibits mTOR activity (only approved for TSC). Because both options have severe limitations, there is a major need to better understand the mechanisms leading to seizures to improve life-long epilepsy treatment in TSC and FCDII. To investigate such mechanisms, we recently developed a murine model of fMCD-associated epilepsy that recapitulates the human TSC and FCDII disorders. fMCD are defined by the presence of misplaced, dysmorphic cortical neurons expressing hyperactive mTOR – for simplicity we will refer to these as “mutant” neurons. In our model and in human TSC tissue, we made a surprising finding that mutant neurons express HCN4 channels, which are not normally functionally expressed in cortical neurons, and increased levels of filamin A (FLNA). FLNA is an actin-crossing linking molecule that has also multiple binding partners inside cells. These data led us to ask several important questions: (1) As HCN4 channels are responsible for the pacemaking activity of the heart, can HCN4 channel expression lead to repetitive firing of mutant neurons resulting in seizures? (2) HCN4 is the most cAMP-sensitive of the four HCN isoforms. Does increase in cAMP lead to the firing of mutant neurons? (3) Does increase in FLNA contribute to neuronal alterations and seizures? (4) Is the abnormal HCN4 and FLNA expression in mutant neurons due to mTOR? These questions will be discussed and addressed in the lecture.

Lifelong devotion to headache research has led to many discoveries. First a series of studies of brain blood flow during attacks of migraine. The results showed changes compatible with cortical spreading depression in migraine without aura effectively negating the then prevailing vasospastic/ischemic theory. In migraine without aura no changes in brain blood flow. This difference was crucial for the separation of migraine with aura and migraine without aura in the first and subsequent editions of the international headache classification headed by me. Then a human migraine provocation model that has elucidated the molecular mechanisms of migraine. Successively we showed in series of papers the importance of nitric oxide, histamine, CGRP, PACAP and prostanoids. Therapeutic effectiveness of antagonizing these provokers by tonabersat, L-NMMA, CGRP receptor antagonists and monoclonal antibodies and of NSAIDs. Present and future attempts to put all these signaling mechanisms into a framework but it is not easy

The study of altered states of consciousness has long had the potential to provide important insight into the nature of consciousness. In recent years there has been a resurgence of research and public interest in atypical or altered states of consciousness. These have focused both on conditions in which consciousness is considered to be impaired due to brain trauma or enhanced in some way through mediation practices or ingestion of psychedelics. The talk will begin with a brief overview of recent scientific approaches to understanding these different types of altered consciousness. The remainder of the talk will focus on lab-based experiments conducted by myself and others looking at the effects of serotoninergic hallucinogens (i.e. psilocybin and LSD) on perceptual and cognitive function. Together this body of research provides important new insights for the scientific study of consciousness and an initial understanding of the neuropharmacological mechanisms underlying conscious experience.

Age-related Macular Degeneration (AMD) and Retinitis Pigmentosa (RP) are vision disorders caused by loss of rod and cone photoreceptors, but downstream retinal neurons also show physiological and morphological changes, resulting in the emergence of hyperactivity and rhythmic firing in many retinal ganglion cells (RGC). We recently discovered that retinoic acid (RA) is a key signal that triggers hyperactivity and that blockers of RA unmask light responses in RGCs that would otherwise be obscured. Recent work is revealing where in the retina circuit RA initiates functional changes. Moreover, interfering with the RA signaling pathway with drug or gene therapy can improve spatial vision in a mouse model of RP, providing a new strategy for enhancing low vision in human RP and AMD.

Although substance use disorders (SUDs) occur commonly in patients with schizophrenia and significantly worsen their clinical course, the neurobiological basis of SUDs in schizophrenia is not well understood. Therefore, there is a critical need to understand the mechanisms underlying SUDs in schizophrenia in order to identify potential targets for therapeutic intervention. Since drug use usually begins in adolescence, it is also important to understand the long-term effects of adolescent drug exposure on schizophrenia- and reward- related behaviors and circuitry. This talk will combine pharmacological, behavioral, electrophysiologic (local field potential recordings) and pre-clinical magnetic resonance imaging (resting-state functional connectivity and magnetic resonance spectroscopy) approaches to study these topics with an eye toward developing better treatment approaches.

L-DOPA-induced dyskinesia is a debilitating adverse effect of treating Parkinson’s disease with this drug. New therapeutic approaches that prevent or attenuate this side effect is clearly needed. Wistar adult male rats submitted to 6-hydroxydopamine-induced unilateral medial forebrain bundle lesions were treated with L-DOPA (oral or subcutaneous, 20 mg kg-1) once a day for 14 days. After this period, we tested if doxycycline (40 mg kg-1, intraperitoneal, a subantimicrobial dose) and COL-3 (50 and 100 nmol, intracerebroventricular) could reverse LID. In an additional experiment, doxycycline was also administered repeatedly with L-DOPA to verify if it would prevent LID development. A single injection of doxycycline or COL-3 together with L-DOPA attenuated the dyskinesia. Co-treatment with doxycycline from the first day of L-DOPA suppressed the onset of dyskinesia. The improved motor responses to L-DOPA remained intact in the presence of doxycycline or COL-3, indicating the preservation of L-DOPA-produced benefits. Doxycycline treatment was associated with decreased immunoreactivity of FosB, cyclooxygenase-2, the astroglial protein GFAP and the microglial protein OX-42 which are elevated in the basal ganglia of rats exhibiting dyskinesia. Doxycycline also decreased metalloproteinase-2/-9 activity, metalloproteinase-3 expression and reactive oxygen species production. Metalloproteinase-2/-9 activity and production of reactive oxygen species in the basal ganglia of dyskinetic rats showed a significant correlation with the intensity of dyskinesia. The present study demonstrates the anti-dyskinetic potential of doxycycline and its analog compound COL-3 in hemiparkinsonian rats. Given the long-established and safe clinical use of doxycycline, this study suggests that these drugs might be tested to reduce or to prevent L-DOPA-induced dyskinesia in Parkinson’s patients.

An imbalance in lipid metabolism in neurodegeneration is still poorly understood. Phospholipids (PLs) have multifactorial participation in vascular dementia as Alzheimer, post-stroke dementia, CADASIL between others. Which include the hyperactivation of phospholipases, mitochondrial stress, peroxisomal dysfunction and irregular fatty acid composition triggering proinflammation in a very early stage of cognitive impairment. The reestablishment of physiological conditions of cholesterol, sphingolipids, phospholipids and others are an interesting therapeutic target to reduce the progression of AD. We propose the positive effect of BACE1 silencing produces a balance of phospholipid profile in desaturase enzymes-depending mode to reduce the inflammation response, and recover the cognitive function in an Alzheimer´s animal and brain stroke models. Pointing out there is a great need for new well-designed research focused in preventing phospholipids imbalance, and their consequent energy metabolism impairment, pro-inflammation and enzymatic over-processing, which would help to prevent unhealthy aging and AD progression.

The factors that underlie an individual’s vulnerability to switch from controlled, recreational drug use to addiction are not well understood. I will discuss the evidence in rats that in individuals housed in enriched conditions, the experience of drugs in the relative social and sensory impoverishment of the drug taking context, and the associated change in behavioural traits of resilience to addiction, exacerbate the vulnerability to develop compulsive drug intake. I will further discuss the importance of the acquisition of alcohol drinking as a mechanism to cope with distress as a factor of exacerbated vulnerability to develop compulsive alcohol intake. Together these results demonstrate that experiential factors in the drug taking context, which can be substantially driven by social isolation, shape the vulnerability to addiction.