Synthetic cannabinoids are the largest and most structurally diverse class of new psychoactive substances, with manufacturers often using isomerism to evade detection and circumvent legal restriction. The regioisomeric methoxy- and fluorine-substituted analogs of SDB-006 (N-benzyl-1-pentyl-1H-indole-3-carboxamide) were synthesized and could not be differentiated by gas chromatography-mass spectrometry (GC-MS), but were distinguishable by liquid chromatography-quadrupole time-of-flight-MS (LC-QTOF-MS). In a fluorescence-based plate reader membrane potential assay, SDB-006 acted as a potent agonist at human cannabinoid receptors (CB EC = 19 nM). All methoxy- and fluorine-substituted analogs showed reduced potency compared to SDB-006, although the 2-fluorinated analog (EC = 166 nM) was comparable to known synthetic cannabinoid RCS-4 (EC = 146 nM). Using biotelemetry in rats, SDB-006 and RCS-4 evoked comparable reduction in body temperature (~0.7°C at a dose of 10 mg/kg), suggesting lower potency than the recent synthetic cannabinoid AB-CHMINACA (>2°C, 3 mg/kg).

Antecedent hypoglycemia suppresses the counterregulatory responses to subsequent hypoglycemic episodes, which can be prevented by normalizing portal-mesenteric vein (PMV) glycemia alone during the antecedent bout. Since the sodium-glucose transporter SGLT3r has been implicated in PMV glucosensing, we hypothesized that PMV infusion of the SGLT3r agonist, N-hydroxyethyl-1-deoxynojirimycin (miglitol), would rescue the sympathoadrenal response to subsequent hypoglycemia. Rats underwent hyperinsulinemic-hypoglycemic clamps on two consecutive days without miglitol infusion (HYPO) or with miglitol infused upstream in the PMV, perfusing the glucosensors, or adjacent to the liver, bypassing PMV glucosensors, on Day-1 or Day-2. Control animals underwent Day-1 euglycemic clamps, followed by hypoglycemic clamps on Day-2. Peak EPI responses for HYPO on Day-2 were significantly blunted when compared to controls. Miglitol infusion on Day-1 proved ineffective in restoring the epinephrine response following antecedent hypoglycemia, but Day-2 miglitol infusion restored EPI responses to control levels. As norepinephrine and glucagon demonstrated similar responses, Day-2 administration of miglitol effectively restored the counterregulatory response following antecedent hypoglycemia. In subsequent experiments we demonstrate similar results with reduced miglitol infusion doses, approaching those currently prescribed for T2D (correcting for rodent size), as well as the efficacy oral miglitol administration in restoring the counterregulatory responses following antecedent hypoglycemia.

Antecedent hypoglycemia leads to a blunting of the sympathoadrenal response during subsequent hypoglycemia, which can largely be prevented by normalizing portal-mesenteric vein (PMV) glycemia during the antecedent bout. As SGLT3 has recently been implicated in PMV glucosensing, we hypothesized that PMV infusion of the imino sugar N-hydroxylethyl-1-deoxynojirimycin (miglitol), a potent SGLT3 agonist, during hypoglycemia would prevent or rescue the sympathoadrenal response to subsequent hypoglycemia. Wistar rats underwent hyperinsulinemic-hypoglycemic clamps on two consecutive days. Control animals were exposed to either euglycemia (EUG-CON: 5.73 ± 0.37 mM) or hypoglycemia (HYPO-CON: 2.39 ± 0.07 mM) on Day 1 without miglitol infusion, followed by a hypoglycemic bout on Day 2. Treatment groups were exposed to hypoglycemia (2.52 ± 0.07 mM) on both days with miglitol (1.45 μmol/kg/min) infused either upstream, perfusing the PMV glucosensors (PORups), or adjacent to the liver, bypassing the PMV glucosensors (PORadj), on Day 1 (PORups1, PORadj1) or Day2 (PORups2, PORadj2). Serial plasma samples drawn on the Day 2 experiment were assayed for glucose, insulin, epinephrine (EPI) and norepinephrine (NE). Compared to EUG-CON, peak EPI responses for HYPO-CON on Day 2 were significantly blunted (34.1 ± 4.3 vs. 15.4 ± 3.5 nmol/L; P < 0.05). EPI responses for PORups1 (11.8 ± 4.7 nmol/L) and PORadj1 (12.83 ± 3.4 nmol/L) were also suppressed on Day 2 compared with HYPO-CON (P<0.05). In contrast, EPI responses for PORups2 (31.5 ± 8.2 nmol/L) and PORadj2 (32.9 ± 13.2 nmol/L) were not significantly different from HYPO-CON (P = 0.74 and 0.90, respectively). NE demonstrated a similar trend to EPI. Conclusion: The impaired sympathoadrenal response following antecedent hypoglycemia in rats is restored by miglitol (NEOH-DNJ) treatment during a subsequent bout of hypoglycemia. Whether this is mediated via PMV glucosensors remains unclear. Disclosure A.J. Jokiaho: None. M. Winchester: None. C. Donovan: None. Funding JDRF